To solve small high speed UAV in the high speed period of longitudinal static instability caused by the problem of insufficient robustness conventional longitudinal control law and design the longitudinal control law based on angular rate instruction inside loop. Taking the certain type high speed target airplane as example to carry out model establishment and feature analysis, design conventional damping inside loop longitudinal control law, and analyze control law robustness difference under low speed and high speed based on parameter uncertainty. Take angular rate instruction inside loop as high speed section longitudinal control law, analyze the instruction inside loop applicability from time domain, frequency domain and robustness, and compare it with the conventional angular rate damping inside loop control law. The results show that the instruction inside loop is more useful for small UAV high speed longitudinal control.