To investigate the expression and the relationship of P16^INK4a and sonic hedgehog signal pathway in cervical squamous cell carcinoma and its precursor lesions. The expression of P16^INK4a, Smo, Ptch and Gli in different HPV types positive cell lines were detected by Western-blot. A tissue microarray constructed with 20 normal cervical tissues and 100 uterine cervical cancers and related lesions (28 squamous cell carcinomas, 26 cervical intraepithelial neoplasia (CIN)Ⅲ, 16 CINⅡ, 12 CINⅠ, 18 tumor-adjacent tissue specimens) was immunohistochemically analyzed with anti- P16^INK4a, Shh, Patched (Ptch), Smoothened (Smo), Gli antibodies. The correlation between their expressions was analyzed. There was no significant difference among different HPV type cell lines regarding the expression of P16^INK4a and Shh, Ptch and Gli proteins(P>0.05). The expression of P16^INK4a and the Hh-signaling molecules was greatly enhanced in cervical carcinoma tissues, compared with that in normal epithelium and tumor-adjacent tissues (P<0.05). There was no significant difference between CINⅠ and normal epithelium(P>0.05), whereas, in case of P16^INK4a, Shh, Smo, and Gli, the differences among CINⅠ, CINⅡ and CINⅢ were significant (P<0.05). The expression of P16^INK4a protein was significantly correlated with that of Shh, Smo and Gli protein in CINⅡ-CINⅢ and cervical carcinoma and was correlated with that of Shh, Smo only in carcinoma tissue. P16^INK4a and the Hh-Gli signaling pathways were extensively activated in the development and evolution of cervical cancer, and the overexpression of P16^INK4a was correlated with Hh-signaling pathways. The abnormal Hh-signaling pathways maybe much associated with Smo protein overexpression induced by Shh, which can upregulate the expression of Gli protein.