Objects: To investigate the role of platelet aggregation function involved in the ischemic cerebrovascular diseases (ICVD) and the correlation of the platelet activating function to PLA polymorphism of GPIIIa gene in the ICVD patients.Methods: The maximum aggregation ratio(MAR) of platelet was analyzed with turbidimetry; plasma levels of TXB_2 ,6-keto-PGF_(1α) , soluble P-selectin were analyzed with radioimmunoassay(RIA), serumal platelet activating factor (PAF) was analyzed with euzymelinked immunosorbent assay(ELISA), and PL~A polymorphism of platelet membrane glycoprotein (GP)IIIa gene were analyzed in the 72 cases of ICVD with onset in 72 hours, including 40 cases of ACI, 22 cases of LI, 10 cases of TIA, and 40 healthy controls.Results:(l)The MAR (49.03±11.54%) level of ICVD patients was markedly higher than those in the controls (P<0.05), particularly in the ACI(P<0.01)(2) The plasma TXB_2(242.22±106.19pg/ml), TXB_2/6-keto-PGF_(1α)  ratios (4.20±1.84) and P-selectin (36.58±9.54pg/ml) levels in the ICVD patients  were markedly higher than  those  in the  controls(77.28 ±27.14pg/ml   1.06±0.35,   19.00±5.77pg/ml   73.71±18.12pg/ml, respectively,  P<0.05), particularly in the ACI patients (329.30±88.11