Abstract: The manned capsule will release trace harmful gas due to material exhaust and human metabolism.In order to ensure that the onboard environment is suitable for astronauts to work and live,it's necessary to detect the composition and concentration of trace harmful gas in the cabin.This paper introduces the common detection methods of trace harmful gases,a ground test system for detecting and calibrating trace harmful gases in manned capsule was established by mass spectrometry,the types of multi-component trace harmful gases in the cabin were analyzed,fragment peaks and graph co-efficients,the experimental study was carried out,the results can provide designbasis and optimizationparameters for in-or-bit application of trace harmful gas detection and calibration system of manned capsule.