Objective To investigate the factors influencing the establishment of melanoma metastasis model in C57BL/6J mice, including the mode of tumor inoculation, the number of cells inoculated and the cycle of tumor formation. Methods Culture of mouse melanoma cells B16F10. 1) Eighteen male mice were randomly divided into three groups, and received 100μL(3 ? 106 cells) melanoma cell suspension by intravenous , intraperitoneal and subcutaneous injection, respectively.After two weeks, mice were dissected and observed the tumor growth and metastasis; 2)Eighteen male mice were randomly divided into three groups, tail vein was injected with 3 ? 106 cells, 1 ? 106 cells, and 3 ?105 cells respectively. After two weeks, mice were dissected and observed the tumor growth and metastasis;3) Eighteen male mice were randomly divided into three groups, tail vein was injected with 1 ? 106 cells, mice were dissected at one week, two weeks and three weeks respectively to observe the growth and metastasis of the tumor. Results 1) The success rate of lung metastasis was 100% in mice injected with tail vein, but the lung metastasis was not found by intraperitoneal injection and subcutaneous injection. 2) When the number of inoculated cells was 1 ?106, the metastatic melanoma nodules were of moderate size; when the number of inoculated cells was 3? 106, the number of melanoma cells with lung metastasis was too much; when the number of inoculated cells was 3 ? 105, the number of melanoma cells with lung metastasis was too small .3)After intravenous injection of melanoma cells in the tail vein for two weeks, significant metastasis of melanoma cells could be observed without causing death in mice; after three weeks of feeding, the number of lung metastases in melanoma cells was too much, and more than half of the mice died; for one week, the number of lung metastases in melanoma cells was too small. Conclusion 1?106 mouse melanoma cells were injected into the tail vein for two weeks, which is a recommended method for the preparation of melanoma metastasis model in C57BL/6J mice.