Objective To define the function of WNT7b in the progression of malignant melanoma, and its potential regulatory role by which it promotes melanoma cells to undergo invasion and metastasis. Methods Initially, intrinsic WNT7b expression level was tested in A875, SK-MEL-28, and A375 cell lines by RT-PCR and Western blotting. The intervention of WNT7b in A375 cell line was performed by transiently transfected with small interfering RNA and its effect on the cellular function was also analyzed by flow cytometry analysis, scratch assay and Transwell assay, respectively. Then western blotting was used to detect the expression of epithelial-mesenchymal transition(EMT) related markers and key members of matrix metalloproteinase(MMP) family closely related to the carcinogenesis of melanoma. Results WNT7b was expressed in A375, SK-MEL-28 and A875 cell lines, among which A375 demonstrates the highest WNT7b expression. Our cellular study showed that upon knockdown of WNT7b expression in human A375 cell line, the cell cycle was arrested at G1 phase, the cell migration and invasion ability were significantly inhibited. In addition, WNT7b knockdown led to E-cadherin up-regulation and N-cadherin, vimentin, Snail1 down-regulation. Further detection on matrix metalloproteinase family members found that MMP2, MMP7 and MMP9 were reduced. Conclusion WNT7b may induce EMT through matrix metalloproteinases in human malignant melanoma cells, thereby promoting cells migration and invasion.