To find effect of lysate of spleen cells after LDR on NK activity of CD,57, cells or non-CD,57, cells. Lysate of spleen cells after LDR were extracted. McAb (anti CD,57, cells) was used to separate CD,57, cells from human peripheral blood by Panning direct method. The CD,57, cells and non-CD,57, cells were used as effective cells.K,562, cells labeled by ,3,H-TdR were used as target cells. The ratio of effect cells to target cells was 10:1.NK activity of CD,57, cells or non-CD,57, cells with the lysate of spleen cells after LDR was reflected by the efficiency of anti tumor cells. The 3H-TdR incorporation in K,562, cells cultured with non-CD,57, cells was significantly lower than that with CD,57, cells. After use of the lysate of spleen cells after LDR, NK activities of NK cells and non-NK cells were 1.24 and 1.58 respectively. They were both increased obviously compared with control groups. The effect of anti K,562, cells of non-NK cells is even greater than that of NK cells. The lysate of spleen cells after LDR can enhance the effect of both non-NK cells and NK cells.