【Abstract】 Objective To study the succinic acid metoprolol ordinary particles with homemade slowrelease the pharmacokinetic behavior of micro pill, verify that slow release characteristics of slow release micro pill and lay the foundation for later research on sustainedrelease preparations. Methods Rats were randomly divided into normal group, lowdose group, each group of male and female 3 only. The normal group was tresated with single oral metoprolol succinic acid in rats of ordinary particles. The slowrelease group was treated with a single oral dose of succinic acid such as metoprolol sustainedrelease micro pill. The LC MS/MS method was used to detect the blood drug concentration. Results Statistical results shown that the two formulations of AUC (0 t), AUC (0 up), Cmax and the MRT (0 t) and the MRT (0 up), t1/2 z, Tmax were significantly different. Conclusion Homemade succinate metoprolol sustainedrelease micro pill has significant sustained release characteristics.