In order to overcome the insufficient of the light energy diffracted by common two dimension grating in dynamic interferometry， diffraction efficiency of the cross phase grating and phase chessboard were derived using scalar analysis and Fourier method, and selection scheme of optimum operation orders was studied. The analytical result of their diffraction efficiency demonstrates that if the cross phase grating is chosen, the(0, ±1)th and(±1,0)th orders should be selected as operation orders, and utilization rate can reach 54.4%; If the phase chessboard is chosen, (±1，±1)th orders is selected as operation ones, and utilization rate can reach 65%. Application effect of these two phase grating are compared in dynamic interferometer. When (±1，±1)th is selected as operation orders, the experimental results indicates that application effect of phase chessboard is better than that of cross phase grating. So influence of insufficient light energy on the measurement result can be eliminated by using phase chessboard and selecting (±1，±1)th as operation orders.