Abstract: Objective: To explore the significance of cervical acid phosphatase (CAP) in the early diagnosis of cervical cancer. Methods: The CAP expression of cervical smears of 350 cases was detected by immunohistochemical staining method with Mark-PAP kit. The red granular deposit in cytoplasm was regarded as CAP positive,which was compared with the Results diagnosed by Thinprep cytologic test(TCT) . Results: The CAP expression of the cervical smears of the patents with cervical cancer was confirmed,while CAP was negative in normal and inflammatory cervical cells. The Results of the CAP test and TCT test were consistent. Conclusions: The CAP expression may be instructive significance in the early diagnosis of cervical cancer.