Objective To observe the expression of connexin 43 (Cx43) and luteinizing hormone receptor(LHR) during the follicular development in mouse ovaries and the effect of luteinizing hormone(LH) on the expression of Cx43, providing experimental evidence for the relationship between the two molecules and the follicular development. Methods Eighty mice were divided into 8 groups with the ages of 1-day-old, 4-day-old, 7-day-old, 2-week-old, 3-week-old, 4-week-old, 6-week-old and 8-week-old, 10 mice for each group. Hematoxylineosin (HE) staining was used to observe the ovarian morphology and calculated the volume fraction of granulosa cells. Immunohistochemistry and Western blotting were used to observe the expression of Cx43 and LHR in ovarian tissues. Western blotting was used to observe the expression of Cx43 in the ovaries after incubation with different concentrations of LH. Results The HE staining results showed that there were primordial follicles, primary follicles in 1-day-old, 7-day-old, 2-week-old and 3 to 4-week-old mouse ovaries, respectively, corpus luteum appeared in 6 to 8-week-old mouse ovaries. The volume fraction of granulosa cells was significantly increased in the ovary after 2-week-old. The results of immunohistochemistry showed that Cx43 expressed in cell membrane of granulosa cells at different stages of the follicles and LHR was expressed in the cytoplasm of the theca cells, granulosa cells and oocytes. After 2 weeks of birth, the expression of Cx43 and LHR increased significantly in ovaries, and raised gradually with the follicular development and then maintained a relatively high level at 3-week-old, 4-week-old, 6-week-old and 8-week-old mouse ovaries. Intervention of LH increased the expression of Cx43 in ovarian tissues. Conclusion Cx43 and LHR play important roles in follicular development and the expression of Cx43 in granulosa cells may be regulated by LH through LHR.