To evaluate the effects and interactions of these factors in CIN in a Chinese cohort. A total of 180 participants, including 61 normal cervix (NC), 59 CIN-I, and 60 CIN-II/III women were enrolled. We measured the serum folate, expressions of hnRNP E2, HPV16 L1, and L2 protein. The levels of serum folate in CIN-I and CIN-II/III groups were lower than the NC group. The expression of hnRNP E2 in the CIN-Ⅱ/Ⅲ group was significantly lower than the NC group (P < 0.001). The expressions of HPV16 L1 (P < 0.0167) and L2 (P < 0.001) proteins in the CIN-Ⅱ/Ⅲ group were significantly lower than the CIN-Ⅰ group. Folate deficiency, low expression of hnRNP E2, down-regulation of HPV16 L1 and L2 proteins presented interaction effects both in CIN-I and CIN-II/III groups. Their synthetic effect could promote the process of the cervical lesions into a high-grade CC development.