Abstract: Microwave power transmission（MPT）design and demonstration are key jobs in development of space solar power station（SSPS）in China，while retro-directive microwave power beam steering is a primary part of MPT.Research on retro-directive microwave power beam steering was conducted under the prerequisite that the power transmitting array was with an ideal profile.The position and attitude errors of structural modules had seldom been considered of the power transmitting array in space environment.With respect to the four-phased missions of SSPS development in China，the influence of position and attitude errors on power density at the rectifying array and beam steering error was investigated.After the software retro-directive microwave power beam steering was preliminarily demonstrated，software retro-directive beam steering based on phase compensation was proposed，aimed at correcting the position and attitude errors of array modules.The correction effect was simulated and analyzed.The proposed software retrodirective beam steering based on phase compensation has remarkable correction ability for the position and attitude errors of array modules.This article presents guidelines for MPT system design and assembly.

Key words: space solar power station, microwave power transmission, retro-directive beam steering, power density, pointing error