Abstract: The national high-precision GPS network for geodetic control is surveyed from 1991 to 1997. The GPS observation data are processed by GAMIT software. GAMIT baseline solution are used as observations for integrate adjustment. In this case the outlier baseline is very difficult to find out from 4 935 independent baselines. This paper uses correlation analysis theory to snoop the outliers. In the adjustment the outliers are kept but down weighted. This theory can find out multi-outliers in correlative observations, and reduce the influence of the outliers. This paper also gives the step and principle for this outlier analysis theory. And gives the comparison of the result of the national high-precision GPS network with outlier analysis.