A study on micromorphology of aridosols in the plain of the south of Xinjiang and origin of parent materials was carried out in this paper by means of field investigation, scanning electric microscope, polarizing microscope, physical and chemical analyses. The results are as follows: Aridosols in the plain of the south of Xinjiang consist largely of sandy primary minerals composing skeleton. Among the sandy primary minerals there are a mass of plasmas made up of fine silty primary mineral, cryptocrystalline and microcrystalline carbonate, and clay. A majority of primary minerals keep intact appearance. From the surface to the bottom horizon skeleton increases and plasma decreases. The aridosols in the plain of the south of Xinjiang have porphyroskelic fabric, agglomeratic fabric and bleached sand fabric. pedological features of aridosols in the plain of the south of Xinjiang are iron, carbonate and gypsum concentrations. The shape of carbonate and gypsum relates to its content. The aridosols in the plain of the south of Xinjiang contain a great quantity of the carbonate in the shape of interflorescences, cutans, nodules, clots and autogenous calcite and accumulates an abundance of gypsum in the form of cryptocrystalline, microcrystalline, needle-shaped, spindle-shaped fibrillar crystals. In ferri-argillic horizon, clay and silt become more and iron concentrations exist in the form of the matrix stained by iron. Quartz grain surface textures indicate: parent material of aridosols in the plain of the south of Xinjiang moved a short distance, and was affected by several factors, especially wind.