Abstract: Objective The study was carried out on time limit of ACP and sperm positive－ detected in mixed spot. Methods 600 vaginal swabs from living body after sexual intercourse were tested by routine and three－ blindness methods.Results The longest time limit of ACP which was positively detected is 255h, average time limit is 52h, 41.3％ of those samples was ACP－ detected in positive degree (＋＋ ). The longest time limit of sperm positively detected is 132h, average time limit is 29h. The number of sperms observed in 34.3％ of those samples with positive result, is from 6 to 10/HP. Conclusion This study is helpful to forensic identification of sex cases.

Key words: living body, mixed spot, ACP, sperm, time limit