Abstract: For unclear and inaccurate performance of status evaluation of relay protector, an improved fuzzy-gray method was proposed for the status evaluation problem. Firstly, an index system is constructed from aspects of historical conditions, maintenance conditions and monitoring conditions. Gray point is used to describe inaccuracy of evaluation information. Then nonlinear membership functions are constructed to attain membership, so as to get fuzzy-gray matrix. Finally fuzzy-gray status evaluation for relay protector is carried out, and evaluation result is re-optimized by weighted average operator. The example shows that the method can reflect operating condition of relay protector more accurately.