Abstract: An artificial random disturbance is carried out for some seismological observation data in the allowance range of seismological observational error with random disturbance method.On the basis of this,the deviations of the 6 parameters(b value,η value,S value for degree of seismicity,H value for seismicity scale,equivalent earthquake M and frequency N)are analyzed with the data before and after the disturbance,in order to find out the effect of seismological observational error on seismological parameters.