This paper investigated a robust global fast terminal sliding mode control approach for quadrotor helicopters with time-varying uncertainties. The controller adopts inner-outer loop control structure. The inner loop is the attitude subsystem, while the outer loop is the position subsystem. Based on the global fast terminal sliding mode control theory, the position and attitude subsystems are designed respectively, and the intermediate command generated by position subsystem is passed to the attitude subsystem. The proposed control scheme is to achieve the fast, high precision and finite time control performance. Simulation results show that the proposed control strategy is effective and robust in the presence of time-varying uncertainties.