The weathering degree of feldspar in 3 sets of profiles of red and yellow soils was studied. In <2 micron fractin of red soils derived from basalt, the content of feldspar is <6g kg^-1. In 2-10 micron fraction, Xuwen laterite and Zhangpu lateritic red earth contain<4 g kg^-1 feldspar; however, Chengxian red earth contains<7g kg^-1 Ca feldspar, and other feldspars are 18-51g kg^-1. In 10-50 micron fraction, besides Chengxian red earth still contains more feldspar, K and Na feldspars in surface horizon of Zhangpu lateritic red earth are> 29g kg^-1. For red soils derived from granite, the contents of feldspars in <2 micron fraction are similar to that of red soils derived from basalt In 2-10 micron fraction, Guangzhou lateritic red earth contains <2g kg^-1 K and Na feldspars, Qianshan red earth 27-49g kg^-1, Huangshan red earth 42-84g kg^-1, but the content of Ca feldspar for all the soils is less than 8g kg^-1. The contents of feldspars in 10-50 micron fraction are similar to that in 2-10 micron fraction, but the amounts of K and Na feldspars in Qianshan and Huangshan red earths are higher. In<2 micron fraction of mountain yellow soils derived from granite, K and Ca feldspars are less than 5g kg^-1 and Na feldspar is usually more than 10g kg^-1; in 2-10 micron fraction, Ca feldspar is less than 7g kg^-1, but K and Na feldspars are 5-100g kg^-1; in 10-50 micron fraction, Ca feldspar is less than 9g kg^-1, K feldspar varies greatly between 14-217, and Na feldspar changes from 31 to 170g kg^-1.