Abstract: Many DOA estimation algorithms, reported in the past literature, are presented and used with the problem that the elements of smart antenna arrays are usually of no direction. The paper analyzes the influence to DOA estimation by MUSIC algorithm when the antenna elements have direction. The effect of mutual coupling is calibrated and some factors that influence the DOA resolution are analyzed. The simulation results are compared and the conclusion is reached that element direction, the direction of array and SNR have great effect on DOA resolution.