Abstract: The influence of mounting angle error in balance calibration for high lift-to-drag ratio models was analyzed. In the calibration of balance, there are two main mounting angles that affect the calibration results, which are attack angle and roll angle. The research shows that, these angle error requirements vary with different components and different coefficients. These angle errors can be allowed at the degree level for three force components and rolling moment, and minute level for pitching and yawing moments. The attack angle error for interference coefficient of normal force to axial force, as well as the roll angle error for interference coefficient of normal force to lateral force, can only be allowed at the second level. It will be difficult to control these two angle errors. According to the aerodynamic force of high lift-to-drag ratio model in wind tunnels, the attack angle error could be relaxed to minute level, and the roll angle error will be allowed at the second level. These angle errors could meet the requirement only with high-precision angle measuring equipment.