Objective? To analyze the application value of colposcopy and biopsy of suspicious lesions in cervical precancerous lesions screening. Methods? A total of 80 patients with cervical precancerous lesions admitted to Maoming Maternal and Child Health Hospital from June 2019 to June 2020 were selected as the research objects.All the 80 patients were confirmed by pathological examination. Colposcopy and biopsy of suspicious lesions were carried out for all patients，and the application effect of colposcopy and biopsy of suspicious lesions under microscope were analyzed. Results? Pathological diagnosis results were 24 cases of cervicitis，36 cases of CINⅠ， 12 cases of CINⅡ，6 cases of CIM Ⅲ，2 cases of early invasive cancer；colposcopy and microscopic biopsy of suspicious lesions showed that 11 cases of cervicitis，the positive detection rate was 45.83%，24 cases of CINⅠ，the positive detection rate was 66.67%，10 cases of CINⅡ，the positive detection rate was 83.33%，5 cases of CIN Ⅲ to positive detection rate was 83.33%. The positive detection rate of 2 cases of early invasive carcinoma was 100.00%. The positive detection rate of biopsies from suspicious lesions by colposcopy and specular microscopy was lower than that by pathological examination，and the differences between groups were statistically significant（P＜0.05）. Conclusion? In the screening of cervical precancerous lesions，colposcopy and biopsy of suspicious lesions under the microscope，the more serious the degree of lesions，the higher the diagnostic effect of this method，which has the value of promotion.