Abstract:Gypsum leaching method was employed to study the mechanism of cumulic cinnamon soil phosphorus leaching. The results indicated that macro- pore are widely distributed in cumulic cinnamon soil, probably was the main pathway of soil phosphorus leaching losses. Gypsum suspension penetrated through root channel could reach to 53cm from ground in soil profile, and to approximately 90cm in depth through holes of soil animals (perhaps earthworm). Soil profile samples taken from soil treated with 200mg/kg P solution (with gypsum suspension as a indicator) had evidently highest Olsen-P concentration compared with that from bulk samples and no P treated samples (ck) ,and no differences were observed for Olsen-P concentration for bulk soil samples.