The fixed-wing micro air vehicle （MAV） is characterized by low speed and small moment of inertia， which make it susceptible to significant changes in angle of attack due to atmospheric disturbances during flight. Subsequently， the angle of pitch oscillates under the restoring moment of the angle of attack， and the longitudinal static stability has a certain impact on the pitch attitude control quality of MAV. To enhance the pitch attitude control quality of MAV， this paper first proposes an evaluation method for MAV pitch attitude control quality under different longitudinal static stabilities. The method defines the variance and range during angle of pitch’s oscillation to represent the pitch attitude control quality. Subsequently， aiming for optimal control quality， the control parameters of the MAV flight attitude control system are adjusted under different static stabilities. By studying the variation law of optimal control quality under different static stabilities， the influence of MAV longitudinal static stability on pitch attitude control quality is obtained. The results indicate that there is a certain nonlinear relationship between pitch attitude control quality and longitudinal static stability. An increase in either longitudinal static stability or instability will intensify the oscillation of MAV pitch attitude under atmospheric disturbances. MAV with longitudinal neutral stability exhibit optimal pitch attitude control quality.