Objective To explore the value of endocervical curettage (ECC) in the detection of high-grade cervical squamous intraepithelial lesion (HSIL). Methods We retrospectively analyzed the clinical features and colposcopical characteristics of 678 female patients with complete clinical data. Results Among 678 cases, 391 cases were confirmed by cervical biopsy only and 7 cases by ECC only (57.67% vs. 1.03%, P < 0.001). ECC checked out 287 HSIL patients (42.33%, including cervical biopsy positive and negative cases) and cervical biopsy checked out 671 HSIL cases (98.97%, including ECC positive and negative cases). There were 68 positive ECC cases in the conversion area of Type 1+Type 2 and 247 positive ECC cases in the conversion area of Type 3(33.33% vs. 52.11%, P < 0.001). The positive rates of ECC in patients≥45 years old and < 45 years old were 145 and 170, respectively (55.13% vs. 40.96%, P < 0.001). Conclusion The cervical biopsy plays a dominant role in the detection of HSIL, and ECC can only be used as a supplement to it. Female patients older than 45 years or with Type 3 transformation zone examined by colposcopy should be concerned with cervical lesions.