Abstract: For arbitrary multiple-input multiple-output (MIMO) sparse arrays, two 3D imaging methods are proposed, namely MIMO single-shot imaging mode and phased array multi-frame joint imaging mode. In this paper, we analyze the differences of the angular resolution and the SNR between those two modes. About the angular resolution, the MIMO mode is equivalent to the resolution of the virtual receiving array. As for the phased array mode, if we adopts the multi-frame jointed imaging method, the synthesized beam pattern is the product of the transmitting beam pattern and the receiving beam pattern, and the resolution is also equivalent to the resolution of the virtual receiving array. About the SNR, the ratio of the phased array mode to the MIMO mode is the number of the transmitting array. The difference and connection between sparse array and evenly full array are discussed, and the beam pattern of sparse array is equivalent to the 2D windowed fast Fourier transform(FFT) of evenly full array, and the 2D windowed FFT widens the pattern of sparse array. MIMO single-shot imaging mode is suitable for application scenarios with high real-time requirements, and phased array multi-frame joint imaging mode is suitable for application scenarios with high SNR requirements.