Experimental studies indicated that the killing process of schistosomes induced by praziquantel comprises two aspects, i.e. the direct effect of praziquantel on schistosomes and the host immune reaction. The former one appears in stimulation of worm activity, spasmodic contraction of worm musculatures and severe damage to the tegument, which results in hepatic shift of schistosomes, influence on the nutrition absorption, excretion/secretion and defense function of the tegument, followed by the secondary interference with the worm metabolism. While the latter one involves the destruction of the host concomitant immune mechanism after tegumental damage and peeling, which is unfavorable for worm survival. Particularly, the exposure of the worm surface antigen provides a target which can be attacked by specific antibodies. Therefore, the antischistosomal activity of praziquantel is immune-dependent. In this paper some host factors involved in the killing process of schistosomes induced by praziquantel were summarized.