Objective: To investigate process parameters and powder characteristics of Pheretima after low temperature pulverization. Method: Pheretima was crushed again by vibration type low temperature ultrafine pulverizer after it was crushed to uniform particle size with high speed grinderof Chinese medicine

sampling every 3 min until all samples out of machine by 25 min

then particle size

specific surface area and porosity of samples were tested. Result: With increasing of grinding time

particle size decreased gradually

then particle size increased after agglomeration of particles;specific surface area and porosity increased firstly and then decreased.Adsorption-desorption curve showed that relative pressure concentrated in 0.8-1.0 when condensation and evaporation occurred;Adsorption quantity of N2 in sample was maximum after crushed 9 min

and it had significant differences with other samples. Conclusion: Pheretima could be crushed to micron level by vibration type low temperaturepulverization

low temperature pulverizationcould guarantee active ingredients in Pheretima unchanged

and it was not easy to gather after crushed to appropriate particle size

which reached particle design requirements of Pheretima in Xiaojin pills.