T he appearance and development of the at tack helicopt er put forw ard more s trict requirement s f or the recoil force of cannon. It’ s an import ant task in the modern cannon t echnology to depress the recoil f orce of cannon. T he FORC principle ( the force optimized recoil cont rol principle) is a new theory and method t o depress the recoil f orce of small-bore cannon. T he writer analyzes the specific property of FORC principle grounded on theoret ical studies , and gives a FORC device as an example, and builds the dynamic model of the FORC device with Bond-Graph theory of syst em dynamics , and imitat es w ith comput er, get s the results curves of dynamic proces s, t est s and verif ies the f easibilit y of FORC principle.