The torque ripple and the torque jumping exist in the electromagnetic torque of reaction wheel.The mechanisms of these two kinds of non-ideal electromagnetic torque are analyzed.The simulation model of micro-satellite attitude control system controlled by reaction wheel is constructed.Then the effect of the torque ripple coefficient,the torque ripple frequency,the torque jumping amplitude,and the duration of jumping torque on micro-satellite attitude are analyzed.Finally the methods to eliminate the non-ideal electromagnetic torque are proposed.The results show that the effect of non-ideal electromagnetic torque cannot be neglected in case that the required controlling precision of satellite attitude is higher.The ripple torque and the jumping torque make satellite attitude generate identical frequency ripple and bias error,respectively,and the effect of these two kinds of torque on micro-satellite attitude is maximum under zero-crossing rotate speed of reaction wheel.The methods,such as preventing zero-crossing rotate speed of reaction wheel,improving the torque ripple frequency,lowering the torque ripple coefficient,and decreasing the torque jumping amplitude and duration,can reduce the effect of non-ideal electromagnetic torque on satellite attitude effectively.