Objective：To investigate whether miR-16 affected the biological function and anti-tumor activity of natural killer（NK）cells by regulating NKG2D expression. Methods：The control mice and miR-16/15a-/- mice were subcutaneously injected with MC38 cells to prepare the colon cancer tumor model，and the growth of transplanted colon cancer in miR-16/15a-/- mice and control mice were observed. Then，the transcription level of miR-16 in NK1.1+NKG2D+ cells and NK1.1+NKG2D- cells was compared under physiological or tumor-bearing conditions in wild-type mice. Finally，in comparison with wild-type mice，we analyzed NKG2D expression，interferon-γ（IFN-γ） production and cytotoxicity of NK cells in miR-16/15a-/- mice. Results：Compared with the control mice，the growth of MC38 transplanted tumor was significantly inhibited in miR-16/15a-/- mice. The transcription level of miR-16 in NK1.1+ NKG2D+ cells was significantly lower than that in NK1.1+NKG2D- cells in normal mice，while there was no significant difference between the two groups in tumor-bearing mice. Compared with the control mice，NK1.1+NKG2D+ cell frequency and NK cell activity did not change significantly in miR-16/15a-/- mice. Conclusion：MiR-16/15a knockout inhibited the growth of MC38 transplanted tumor，while the ratio and function of NK cells in miR-16/15a knockout mice and the activity of NK cells in the tumor-bearing state did not significantly change，suggesting that miR-16/15a dificiency does not inhibit the growth of MC38 transplanted tumor though NK cells.