On-line verification plays an important role in improving operation level of power grid. However， when it applies to large-scale grid， it is often difficult for users to determine the weak degree of relay settings， because many relays cannot satisfy the verification requirements. Taking distance protection for instance， the operating incorrect probability of the relays when verification standards are not met is analyzed and relative load loss is used to quantify the results. Thus the weak region on-line identification of relay settings based on risk under current operation mode can be implemented. In the meantime， the weak degree analysis of relay settings under historical operation modes from the perspective system operation fluctuation is also given. The two methods serve together to provide users with basis for timely making reasonable relay settings regulation strategy. The proposed method is verified the rationality and feasibility with one project instance.