Interference test were made by clindamycin phosphate injection of different batch number and horseshoe crab reagent produced by different factories.When clindamycin phosphate injection was diluted to 2mg/mL, it had no interference to horseshoe crab reagent.Horseshoe crab reagents of sensitivity ≤0.5 EU/mL were used in the bacterial endotoxin assay.This method could substitute former pyrogen assay.