Abstract: Objective: To assess the clinical significance of atypical squamous cells of undetermined significance (AS -CUS) and the value of Human Papillomavirus (HPV)testing. Methods:From August 2007to June 2009, a total of 119 wom-en were diagnosed with ASCUS by cytological testing at Zhongshan Hospital. Biopsies were taken during colposcopy, and all cases were tested together with high-risk HPV-DNA testing. Results: Among the 119 patients investigated, 43patients were diagnosed with cervical intraepithelial neoplasia (CIN). The detection rate of CIN in the HPV positive group was a lot higher than that of the negative group. Of the51cases positive for HPV, 33cases also had CIN (χ2=32.9, P< 0.05). No sig -nificant difference was found in the sensitivity between the HPV test and colposcopy ( P>0.05). Conclusion: Colposcopy and high risk HPV test are both effective methods to detect ASCUS. When used in combination, they can also improve de-tection rate and accuracy of cervical intraepithelial neoplasia (CIN). Attention must be paid to the increased occurrence of CIN in women with ASCUS and knowledge of CIN rates should be used to strengthen management of the disease.