【Objective】The aggradation red earth sediment is widely distributed on terraces in the middle and lower reaches of the Yangtze River, especially in the piedmont of Lushan Mountain in China. Their sequences haves well recorded the weathering history during Quaternary in South China. Therefore, the objectives of this research were to(1)investigate the micromorphological characteristics of aggradation red earth sequence and(2)reveal the paleosol pedogenic environment. 【Method】The research profile was L-HH(29°32 '07.88 "N, 116°04' 19.53"E, H=87 m)at the eastern piedmont of Lushan Mountain. Nine undisturbed samples were collected from the different pedogenic unit and made into thin sections, which were observed by plane polarized(PPL)and crossed polarized light(XPL)using Zeiss Axio Lab. A1 polarizing microscope in the laboratory. A total of 159 bulk samples were collected along with the profile at 5～6cm intervals. Moreover, particle size, chroma, susceptibility and geochemical data of the 159 bulk samples were measured.【Result】L-HH profile can be divided into reticular red soil unit(RRS), reticulated yellowish-brown soil unit(RYB)and yellowish-brown soil unit(YBS)from the bottom up. The soil matrix under Fe-impregnation was mainly composed of clay and colloid, the content of which is up to 50%～70%. The fragments included quartz, plagioclase and muscovite, while the secondary mineral was mostly illite and vermiculite. Also, heavy minerals that were observed included apatite, zircon, rutile and tourmaline. These results suggest in general that the soil units have a moderate-strong degree of chemical weathering. However, there were differences in detail among different units. The voids types of RRS are dominated by large linear channels with good connectivity and smooth wall. Also, the pedological features were mainly composed of coating, ferromanganese nodules, and diffuse concentric rings. Additionally, the illuvial coating developed along the voids wall and formed interbedded layers. Mn-coating was mostly superposed on the Fe-coating, and some pores were filled with the coating. Besides, part of the illuvial Fe-clay coating had a decolorization phenomenon. Thus, the pedogenic environment of RRS was characterized by strong summer monsoon, high soil moisture content, and increased seasonal climate contrast. Furthermore, the voids types of RYB were dominated by vughs, chamber voids and well-connected channels. Fe-Mn features were abundant in the soil matrix. The types of pedological features were rich with Fe masses, ferromanganese nodules and rhizospheric concentric iron-rings scattered in the matrix. The brown-red or grey-black flaky coating was developed repeatedly along the voids wall, and the deposition thickness was increased. Also, the soil moisture decreased, but the alternation between dry and wet was still significant. This, indicated a warm and dry environment. The voids types of YBS were dominated by plane voids, chamber voids, irregular voids, and vughs. Also, the voids’ wall was rough and the channel connection was poor. The pedological features mainly included diffused coating. A thin Fe-illuvial coating was found on some voids wall. During this period, the temperature and moisture conditions became worse. The climate was dry and cool, and the winter monsoon was strengthened. Also, changes of environmental proxies along the profile strongly supported the results of soil micromorphology. From the bottom up, the soil moisture content decreased continuously, and the climate tended to be dry and cool. The micromorphological characteristics support the view that the reticulation process was controlled by iron differentiation. Moreover, the micromorphological characteristics also showed that soil voids and plant roots accelerated the process of reticulation. 【Conclusion】The findings in this study demonstrate that there is a significant correspondence between soil micromorphological characteristics and environmental proxies in the L-HH profile. This is an important indicator for interpreting the pedogenic environment of red earth, monsoon evolution signal. and the reticulated mechanism.