The aim of this paper was to explore the role and mechanism of circHIPK3 in unexplained recurrent spontaneous abortion (URSA). The expression of circHIPK3 and miR-30a-3p mRNA in URSA villous tissues was detected by quantitative polymerase chain reaction. The effects of circHIPK3 on the proliferation and migration of villous trophoblasts were analysed by MTTassay and scratch assay. Hoechst/PI staining was used to detect the effect of circHIPK3 on villous trophoblast apoptosis. The binding of circHIPK3 to miR-30a-3p and miR-30a-3p to Wnt2 was analysed by dual-luciferase assay. When URSA occurred, the expression level of circHIPK3 was downregulated, while the expression level of miR-30a-3p was upregulated in villous trophoblasts. Inhibition of circHIPK3 in villous trophoblasts can reduce the proliferation and migration of villous trophoblasts while promoting their apoptosis. The dual-luciferase assay showed that circHIPK3 was able to interact with miR-30a-3p and increased the miR-30a-3p expression after inhibition of circHIPK3, and if miR-30a-3p was also inhibited it was able to reverse the effect of circHIPK3 on villous trophoblast proliferation and migration. It was demonstrated by prediction and dual-luciferase assay that miR-30a-3p binds to Wnt2, and when miR-30a-3p and Wnt2 are inhibited simultaneously, it has an inhibitory effect on the proliferation and migration process of villous trophoblasts. Downregulation of circHIPK3 expression in URSA leads to increased expression of miR-30a-3p, which in turn inhibits the expression of target gene Wnt2 and exerts a weakening effect on theproliferation and migration process of trophoblasts, thereby decreasing trophoblast invasiveness and shallow placental implantation, which in turn leads to recurrent spontaneous abortion.