In this paper, the formation flight of multiple Unmanned Helicopter (UH) systems is researched and a new decentralized receding horizon formation control algorithm is supposed. The formulation of formation control problem is firstly given where a local tracking controller for each helicopter system is supposed and the flight trajectories are taken as optimizing variables. Secondly, full dynamics of UH system is introduced into the formation control algorithm by a new concept of Formation Control Lyapunov Functions (FCLF). Subsequently, the convergence of the proposed formation control algorithm is ensured by combining the concept of FCLF and some constraints with respect to the optimized variables. Finally, in order to verify the feasibility and validity of the proposed algorithm, the formation flight simulations of 3 UH systems are conducted.