A three-axis stabilized orthographic barrel was designed for aerial survey.This barrel carried an high-definition (HD) digital camera and a micro-TVand realized orthographic observation and photograph with inertial stability by using angular speed closed-loop control mode and inertial pointing position closed-loop control mode.Different from traditional gyro installation in bearing ringthis barrel used independent MEMS GPS integrated navigation system to realize disturbance isolation and orthographic direction.The desired angle position and angle speed compensation equation when the integrated navigation system was installed on the barrel shell were derivedand the design principlemethod and model of control modules were presented.The testing results showed that the stabled line of sight is perpendicular to the groundthe orthographic error can be controlled within 3°which can guarantee the longitudinal and transverse overlapping ratereduce the appearing of aerial photograph hole.