The invention relates to a self-compensation type free up-down pitching coupling mechanism used for carrying out a flight simulation test; the coupling mechanism comprises a free up-down pitching mechanism and a forced up-down mechanism. The coupling mechanism can greatly extend a vertical line displacement motion scope, thus realizing free up-down and pitching coupling vertical short period motions of a plane model in a horizontal wind tunnel, and satisfying vertical pneumatic/motion coupling characteristics and flight quality research demands. Compared with a flight simulator or test flightmeans, the self-compensation type free up-down pitching coupling mechanism is high in repeatability, short in period, low in risks, thus making up disadvantages of existing wind tunnel test means.