The interactions of loureirin A(LA)，loureirin B(LB) and cochinchinenin C(CC) with human serum albumin(HSA) under simulated physiological conditions(pH 74) were studied by pressure-mediated affinity capillary electrophoresis method(P-ACE).The binding constants were 0414×105，0252×105 ，1816×105 L/mol for LA，LB and CC，respectively.The results showed that P-ACE was a useful method to study the interaction between drug and protein.