This contribution proposes to refine the affine model for affine merge coded blocks in decoder sider without additional signaling. In the proposed method, both the base MV and non-translation parameters of affine model are refined to improve the accuracy of the affine model inherited from the previously coded blocks in merge mode. It is reported that on top of ECM-6.0, by applying the proposed method, it achieves {-0.26%(Y), -0.16%(U), -0.19%(V)} coding gain in RA on average with luma coding gain reaching -0.36% on class A1 and -0.50% on classA2.