Override rod linkage form is adopted by the cockpit control units of a certain type of fly-by-wire civil aircraft, and it brings some profits on the weight and maintainability while the problems it resulted in are the failure mode becomes diverse and complicated. For the problem, this paper does a research on the working principle and physical characteristics of the cockpit control units, through modeling and simulation on its normal mode and failure mode, and finally gives an analysis and evaluation for the column force quality of each failure mode. The simulation results reveal the column force quality of each failure mode is acceptable.