Suboptimum performance may be obtained by partially adaptive processing at subarray level where the problem of how to group the subarrays is an important task. A rule named equal noise power method is proposed to divide a uniform linear array which employs amplitude tapering into contiguous subarrays of unequally sized. A set of results of computer simulation aregiven to show that this subarray configuration has few obvious grating lobes while its adapted antenna pattern and adaptive performance in interference suppression are close to that of the full optimum processing.