This paper designs a space-time parallel architecture. This architecture increases the degree of the freedom of the array antenna by adding delay units without increasing the number of elements, so as to obtain the ability to deal with more interferences and realize the separation of the same direction interferences and the desired signal. In the beamforming method aimed at maximizing the output power, the iteration step varies linearly with the ratio of input and output signals, so faster convergence cannot be achieved. In this paper, a beamforming algorithm with exponential step size to maximize the output power is proposed. The iterative step size of the algorithm changes exponentially with the ratio of input and output signals, so the step size can be large when the ratio is large and smaller when the ratio is small, which can ensure stability and converge quickly. Finally, the effectiveness of the method is verified by simulation.