The invention provides a method for rapidly detecting anticoagulant activity of poecilobdella manillensis, which comprises the following steps: step 1, taking living poecilobdella manillensis, draining, weighing and recording; step 2, adding water which is 1.5 times of the weight of the poecilobdella manillensis according to the weighed weight; and step 3, carrying out homogenization treatment on the poecilobdella manillensis living body added with water by using high-speed stirring equipment. And 4, sucking 1g of poecilobdella manillensis slurry by using a dropper, adding 5ml of 0.9% sodium chloride solution, uniformly shaking, extracting for 30 minutes, filtering by using filter paper to obtain filtrate, and titrating. 5, according to the titration detection result, the obtained U value is substituted into a deduced formula y = 10.287 x-13.211, the value x is the U value obtained in the step 4, and the result obtained after calculation is the expected activity of the freeze-dried powder prepared from the poecilobdella manillensis raw material. According to the method, the activity of the sample slurry is directly detected by adding a certain proportion of water into the living body sample for homogenization, so that the process is simplified, and the time is saved.