Objective To improve the Hirudin content determination method of Poecilobdella manillensis. Methods The effect of using white porcelain plates method， two kinds of thrombin solution concentration， several kinds of titration volume on the results of content of Hirudin was studied；The results of 5 batches of samples were compared by two different methods. Results The white porcelain method was used， using two kinds of thrombin solution（40 NIH·mL-1 and 20 NIH·mL-1） and several kinds of titration volume（1～5 μL）， once every minute， the accurate consumption volume of the test sample was determined with two different concentration of thrombin solution， after preliminary tested with the higher one. The blank test was increased， response time was limited for 10 minutes；The linear range of Poecilobdella manillensis was 0. 00678 ~ 0. 0597（r=0. 9983） g·mL-1， The content rang of Hirudin in 5 batches of samples was 156. 68～234. 25U·g-1， the RSD of repetitiveness tests was not more than 5%； The sample solution was stable under 4℃ in 24 hours. Conclusion The improved method was simple and quick， more repeatability and accuracy than the original method， it can be used as a new content determination method of Yunnan Poecilobdella manillensis.