In order to solve the clutter suppression problem of MIMO radar,a rapid dimension-reduced STAP algorithm,Fast JDL (F-JDL) algorithm,is proposed.Firstly,the space-time data is reflected accurately to the angle-Doppler bins of localized processing region by employing an over-complete basis set,which is consisted of all the interested testing angles.Then the matrix block-inversion is used to dispose the clutter covariance matrix.This method combines the advantages of both the JDL dimension-reduced algorithm and matrix block-inversion.The simulation results show that:F-JDL algorithm makes full use of the advantage of MIMO radar of large DOF (Degree of Freedom),and significantly decreases the computational cost and training samples required,which presents better clutter suppression performance.