Based on the laser gyro digital integration circuit,the coefficients between the null shift and current discharge difference,current discharge sum,beam intensity difference are got by precision controlling the parameters changing. Through long time tests to laser gyro,the infection,caused by the precision of these parameters,is got by calculating. In order to make the conclusion validly,the two laser gyros which are different in precision are selected to be tested. The resucts show that the digital integration circuit which is working under now mode infects the precision of laser gyro no more than 1%.