Abstract: The reason why the phased array radar with mechanical scanning and electronic scanning cannot track continuously when the target passes zenith is analyzed: when the azimuth angle of the mechanical axis lags the target by more than 90°, the tracking elevation angle will exceed 90°, which will cause the azimuth error to be incorrect and lead to the loss of the target. A tracking strategy called "clumsy birds fly first" is proposed for targets with theoretical trajectory, that is, design a zenith pass tracking trajectory to accelerate the mechanical axis in advance and offset the electrical axis to track the target. The constraints of the trajectory design are analyzed, a mathematical model is established and solved by the improved crayfish algorithm. Aiming at the problems that the crayfish optimization algorithm is easy to fall into local optimum and the optimization accuracy is not enough, three improved measures are proposed: the good point set initialization method is used to enhance the population diversity; the summer resort strategy of cave group is used to prevent falling into local optimum; the adaptive food intake strategy is used to improve the optimization accuracy. By comparing with other five optimization algorithms, the improved crayfish optimization algorithm is better in terms of convergence accuracy and algorithm stability. This method has been applied to the zenith pass tracking task many times, and the tracking effect of one task is shown, which proves the feasibility of this method.