OBJECTIVE： To investigate the antithrombotic effects of prasugrel hydrobromide acetic acid compound. MEHTODS： Using clopidogrel bisulfate as positive control， automatic thrombus detector was used to detect length， wet weight and dry weight of in vitro thrombus in rats after treated with low-dose， medium-dose and high-dose of prasugrel hydrobromide acetic acid compound and prasugrel hydrochloride （0.05， 0.5， 5 mg/kg， by prasugrel）. The content of cAMP in platelet of rats was determined by ELISA after treated with low-dose， medium-dose and high-dose of prasugrel hydrobromide acetic acid compound （0.05， 0.5， 5 mg/kg， by prasugrel）. The in vivo thrombus in mice was induced by carrageenan. The black tail length and the relative length were measured with vernier calipers after pre-treated with low-dose， medium-dose and high-dose of prasugrel hydrobromide acetic acid compound and prasugrel hydrochloride （0.2， 2， 20 mg/kg， by prasugrel）. RESULTS： After treated with medium-dose and high-dose of prasugrel hydrobromide acetic acid compound and prasugrel hydrochloride， the length of in vitro thrombus was shortened significantly， wet weight and dry weight were decreased significantly， compared with normal control group （P＜0.05 or P＜0.01）. There was no statistical significance in above indexes between prasugrel hydrobromide acetic acid compound groups and corresponding prasugrel hydrochloride groups， between prasugrel hydrobromide acetic acid compound high-dose group and clopidogrel bisulfate groups （P＞0.05）. After treated with medium-dose and high-dose of prasugrel hydrobromide acetic acid compound， the content of cAMP in platelet of rats was increased significantly， compared with normal control group （P＜0.05 or P＜0.01）. After pretreated with medium-dose and high-dose of prasugrel hydrobromide acetic acid compound and prasugrel hydrochlorde， black tail length and the relative length were shortened significantly， compared with model group （P＜0.01）， and above indexes of prasugrel hydrobromide acetic acid compound high-dose group and prasugrel hydrochloride high-dose group were significantly shorter than clopidogrel bisulfate group （P＜0.05）. There was no statistical significance in above indexes between prasugrel hydrobromide acetic acid compound groups and corresponding prasugrel hydrochloride groups （P＞0.05）. CONCLUSIONS： Prasugrel hydrobromide acetic acid compound can significantly decrease the length， wet weight and dry weight of in vitro thrombus， and shorten the black tail length and the relative length of mice. Prasugrel hydrobromide acetic acid compound and prasugrel hydrochloride have similar antithrombotic effects. The above effects are performed by up-regulating the content of cAMP in platelet with prasugrel hydrobromide acetic acid compound.