The utility model relates to a passive servo loading device of trailing type, include by loading object slide rail and base, wherein, by loading object slide rail fixed mounting on the base, installedon by loading object slide rail and can slide on by loading object slide rail by the loading object, all the time, contacted with the following mechanism who is used for the volume of acquireing thedisplacement and follow by loading object synchronous motion by the loading object, following mechanism links to each other with being used for the pressure output mechanism who obtains loading powersize. The utility model discloses following mechanism obtains to be moved through following mechanism driving pressure output mechanism by the displacement volume of loading object through the in close contact with with by the loading object to size through pressure output mechanism acquisition loading power has the advantage that pressure collecting is timely, accurate, and is both sensitive to the displacement by the loading object, also sensitive to loading load. The utility model discloses the system response frequency is more than by loading object motion frequency, can improve system response's promptness and accuracy.