Automotive radar is the key component of driver assistance system. The main current requirements of are high angular resolution, high target detection accuracy, low power consumption, and low cost. However, ambiguous target and low angle measurement accuracy will appear in the multi-target scenario. In order to solve these problems, TDM-MIMO (time division multiplexing multiple-input-multiple-output) radar is implemented to improve the angular resolution. We use the proposed TDM-MIMO LFMCW (linear frequency modulated continuous wave) echo model to derive the range, velocity and azimuth information of the target. And we present a 3D-FFT (three-dimensional fast Fourier transform) scheme to solve the problem of multi-target detection. In the simulation, we effectively solve the accuracy problem in multi-target detection without ambiguity, and the angular resolution is improved by about 14°.