The invention discloses an improved covert fault detection method capable of considering information uncertainty. The improved covert fault detection method comprises the following steps: through the identification of a fault area and the collection of the signals of an information protection system, determining a suspected fault element set and a circuit breaker set; according to a protection rule, analyzing to obtain the expected expression of each signal, and constructing and simplifying an analysis model; then, establishing a target planning function, and utilizing a discrete particle swarm algorithm to carry out optimization solution; aiming at the uncertainty probabilities of different practical situation faults, establishing a solution set evaluation index, and determining a practical optimal solution; and finally, comparing an optimal solution set and a collected signal set to determine protection equipment which has the covert fault. The improved covert fault detection method can improve solving speed and precision and eliminate the situation of the wrong solution or error solution of an original method. Meanwhile, a probability module which considers the information uncertainty is added to distinguish the detection results of different areas. The improved method performs multiple and important functions on the detection of the convert fault of a relay protection device.