Abstract: 【Purpose/significance】By constructing the usability evaluation index system of community Q & A platform and selecting em⁃pirical objects for evaluation, this paper provided data support and reference for the usability optimization of community Q & A plat⁃form【. Method /process】Through literature review and user survey, factor analysis method was to be used to establish the evaluation in⁃dicators of community Q & A platform, MUSA and TOPSIS methods were applied to evaluate the usability of community Q & A plat⁃form.【Result/conclusion】The user measurement results of three community Q & A platforms’usability were obtained, and the opti⁃mal scheme，the worst scheme of three platforms evaluation indicators and the optimal distance and the worst distance of the platform were located and analyzed. According to the results, the optimization and improvement strategy of usability was put forward.【Innova⁃
tion/ limitation】Combined with the advantages of MUSA and TOPSIS, this paper comprehensively used the two methods to deepen the usability measurement research of community Q & A platform, and realized the more detailed and accurate usability measurement by horizontal and vertical comparison. However, there were still some limitations in the number of empirical objects and the number of sample research.