Objective: To optimize percolation parameters of Pheretima. Method: By using external hemolysis method

with solid content and protease activity as indicators

single factor tests were adopted to optimize percolation process. Result: The concentration of urokinase in 25-125 U·mL-1 showed a good linear relationship with soluble circle area

the best percolation processing parameters were:crushed Pheretima to a coarse powder

soaked 0.5 h with percolation rate of 2 mL·min-1

added 8 times the amount of 60% ethanol for percolation;percolate volume

solid content and protease activity were 220 mL

3.252 g

5 624.7 U·g-1. Conclusion: Fibrinogen plate method can be fast

easy and accurate to determine enzyme activity in Pheretima

these optimized process parameters was stable and feasible

it provides new choice for full utilization of active ingredients from Pheretima.