Traditionally, the excitation coefficients of elements in smart antenna has been determined and controlled by using least mean square (LMS) algorithm. It is well-known that the LMS performs poorly in very noisy environment such as in a mobile communication systems. In this paper, a Genetic Algorithm(GA) is utilized for optimizing the excitation coefficients of smart antenna. The performance of the smart antenna based on GA has been evaluated and has been compared with its LMS based counter part. Simulation results showed that the GA has nearly optimal interference cancellation. Other advantages of the GA is its simplicity and fast convergence provided that the parameters are appropriately chosen, which makes it a practical algorithm for determining the excitation coefficients of smart antenna.