There are various system errors in the inertial measurement unit ( IMU). It needs calibration to enhance the accuracy of attitude calculation. The correction matrix is usually determined by the measurement values and their theoretical values at some specially designed positions where the measurement values of sensors also contain various system errors. The error caused by the correction matrix is deduced theoretically, and its influence on the error of attitude parameters is studied. Experimental data are utilized to verify those influences. According to the point design of balance correction, the influence models of balance correction and its structure topology on attitude accuracy are researched in detail. The balance correction is again implemented on the original experiment data. The results at some classic attitude positions show that the balance correction generally reduces the absolute error. The average and peak values of absolute attitude error are decreased to 30. 8% at least with the average balance correction. Moreover, the attitude accuracy of small inclination angle with the average balance correction occupies the similar attitude accuracy under large and medium inclination angles with the traditional correction method.