Abstract: A parameter elimination method to convert a parameter adjustment model to a condition adjustment model was brought forward. Using this method, a parameter adjustment model can be changed into a condition adjustment model through eliminating all the parameters in the parameter adjustment model. As a result, condition equations can be automatically established with computers. Based on the above research, the approach of outlier detecting and locating with the closing errors of condition equations was given. In addition, the feasibility of this method was proved by an example. The result shows that this method can test all the checkout conditions including side and coordinate conditions, raise the capability of outlier detecting and locating in an adjustment system, and make the searching of closed loops in a surveying network realized satisfactorily with computers.