Airborne phased array radar is greatly affected by ground clutter when it is working downwards. Although the space-time adaptive processing (STAP) technology has good performance of suppressing clutter, its performance depends on a large number of training samples and high computational complexity, It is difficult to apply in practice. In order to make up for the shortcomings of the STAP algorithm, an optimization algorithm for local joint processing (JDL) is proposed. When constructing the dimensionality reduction matrix, the method adjusts the selection strategy of the local processing region, four independent auxiliary channels are selected at the clutter ridge corresponding to the main channel to improve the directivity of the beam and cancel the clutter in the main beam. The results show that the optimized method has better clutter suppression performance than the traditional JDL method, further reduces the amount of system calculation, and maintains better stability in the case of amplitude-phase error.