A novel synthesis method of a sparse rectangular planar receiving array (SRPRA) to maximize the power transmission efficiency (PTE ) for microwave power transmission (MPT) is proposed in this paper. The array element positions of the SRPRA are symmetrically distributed among different quadrants such that the array elements at symmetrical positions receive the same power, and the SRPRA adopts a sparse layout. This reduces the number of array elements and simplifies the complexity of the feeding network. An improved adaptive chaotic particle swarm optimization (IACPSO) algorithm is proposed for the optimization synthesis problem of the SRPRA. Through the optimization of the proposed IACPSO algorithm, the optimal element layout of the SRPRA can be obtained efficiently to get the maximum PTE. In addition, we conduct a series of simulation experiments to verify the advantages of the proposed SRPRA model and the effectiveness of the IACPSO algorithm. Firstly, we analyze the effects of different parameters on the synthesis results of the SRPRA. Secondly, comparing the results with those of the sparse random circular aperture array (SRCAA), it is demonstrated that the SRPRA synthesized with the IACPSO algorithm can obtain higher PTE with fewer elements and has a relatively simple feeding network. Finally, compared with the standard particle swarm optimization (SPSO) algorithm, the proposed IACPSO algorithm can effectively and stably obtain the synthesis results of the SRPRA under different parameters. Therefore, the SRPRA is suitable for creating an efficient MPT system.