Adopting the statistic method to calibrate the standard uncertainty,a great number of measured data are needed,and their dis- tribution rule must be known.But it is difficult to be done in practice.Using the grey system theory,a new method of solving the standand devia- tion is proposed in this paper.On this account,evaluating the uncertainty,the account of data and the rule of the distribution will be without spe- cial requirement.The better effect has been obtained during practical application.