The methods of (NH₄) ₂SO₄-H₂SO₄- diantipyryl methane colorimetry and NaOH melting-diantipyryl methane colorimetry were used separately to extract and determine the amorphous titanium and total titanium in some purple parent rocks and soils in the Sichuan Basin.The total/amorphous titanium was defined as/titanium value 0,which was used for estimating weathering degree of purple parent rocks instead of SiO₂/(Al₂O₃+Fe₂O₃) value.The results show that of the contents of total titanium in six purple parent rocks in the Sichuan Basin varied in the range of 2195~2010 g kg^-1,which is a middle level on the high side,and the six parent rocks in terms of lithology were in a decreasing order of shale > mudstone > siltstone > sandstonem.The total titanium was obviously in negative correlation (r=-0.7459) with SiO₂ in these rocks.itanium value was reversibly correlated to weathering degree.According to the titanium value of the rocks,weathering degree of the six purple parent rocks were lined in an rising order of Trias T₁f< Jurassic J₂s< Jurassic J_1-2^z< Jurassic J₃p< Jurassic J₂sn< Cretaceous K₂j.The order of weathering degree of the purple soils based on titanium values basically tallied with that based on SiO₂/(Al₂O₃+Fe₂O₃) values,with correlation coefficient reaching an obvious level (r=0.8615^**).The correlation coefficient between the titanium value of soil colloid and the SiO₂/(Al₂O₃+Fe₂O₃) value also reached an obvious level (r=0.8757^**).The weathering degree showed by the titanium value of the soil is in accord with that showed by purple parent rocks.