Complete reserving logic relations between the fault elements and act of protective relays/circuit breakers trip largely contributes perfect error-tolerance ability and application prospect when complete analytic model（CAM） for power systems fault diagnosis（PSFD）is in analysis process of fault diagnosis rules.In this paper， based on IEC 61850 standard a constructing method of CAM for PSFD which uses substation configuration description（SCD） file of substation system is presented. The protection configuration information of devices and the logical relationships between act of protective relays and circuit breakers trip can be acquired with analyzing SCD file， and CAM for PSFD may on-line form by combining the topology information. Finally， the feasibility of the modeling method as well as CAM itself are verified with a complex fault diagnosis example， and the modeling method presented in the paper is expected to apply to on-line fault diagnosis of power systems.