Abstract: According to a class of H-type double drive gantry system, the problem of decentralized output feedback disturbance rejection control for this kind of system is studied under the effect of modeling error, uncertain parameters and other uncertain interference factors. Firstly, two parallel carriages in the double-drive gantry system are taken as the research object, the considered system is transformed into two interconnected subsystems through proper coordinate transformation. Secondly, on the basis of expanding the lumped disturbance of each subsystem, the observer and disturbance rejection controller of the system are designed for each subsystem by using the generalized proportional integral observer technique and the output feedback dominant technique. Finally, the strict theoretical analysis demonstrates that the tracking error of the whole closed-loop system will be driven to an arbitrary small region exponentially under the given control method. The effectiveness of the algorithm is verified by simulation experiments.