An efficient rate control strategy for H.264 is proposed in this paper, which results an accurate bit stream required for each frame. A solution of the chicken and egg dilemma between rate control and R-D optimization (RDO) in H.264 is given, and hence different bits to different modes are allocated so that the bad situation for the quadratic R-D model is deviated. Simulation results show that the fluctuation of bits and PSNR of each frame in our algorithm is smaller that JVT-G012 while it super performs the method of JVT-G012 in the target bit rate matching. Unlike JVT-F086, RDO only performs once for each macroblock (MB). Therefore, the complexity is similar to JVT-G012.