The size effects on axial compression performances of reinforced concrete column under repeated load are needed. Specimens were designed and tested in accordance with the relevant similarity， whose geometric dimensions are: 400 mm×400 mm×1 200 mm， 600 mm×600 mm×1 800 mm and 800 mm×800 mm×2 400 mm. The result of the experiment， the failure characteristics， crack development process， strength， peak stress， peak strain and stiffness of various specimens were comparatively analyzed. The results show that， within size range of this test， size effect exists on performances of columns.