This paper mainly deals with the problem of Multiple-input multiple-output (MIMO) radar in non-Gaussian clutter modeled as a complex isotropic Symmetric α-stable (SαS) process. The widely separated MIMO radar or Statistical MIMO (S-MIMO) radar is adopted. First, the signal model is developed to the complex isotropic SαS clutter, and then, the S-MIMO Rao detector is derived. To demonstrate the efficiency of the new detector, its performance is compared to that of the well-known Optimum Gaussian (OG) detector of S-MIMO Radar. Monte Carlo simulations are given for the cases of different clutter parameters and transmit/receive antennas. Via several numerical examples, it is shown that the S-MIMO Rao detector can provide excellent detection performance in heavy-tailed clutter compared with the S-MIMO OG detector.