The invention provides a power equipment fault detection method based on a matrix diagram and a confidence coefficient. The power equipment fault detection method includes the steps that the quantity of state of power equipment is collected in real time; early warning processing is carried out on an abnormal quantity of state according to the quantity of state, and fault power equipment is screened out; probabilities of occurrence of theoretical faults of fault power equipment are obtained according to the theoretical faults of the fault power equipment, the abnormal quantity of state corresponding to the theoretical faults, influence quantized values of abnormal quantity of state to the theoretical faults, and influence degree quantized values of the abnormal quantity of state to the theoretical faults; the theoretical faults are faults possibly occurring aiming at the abnormal quantity of state of the fault power equipment; different alarming prompts are given according to the different probabilities of occurrence of the theoretical faults. The invention further provides a power equipment fault detection system based on the matrix diagram and the confidence coefficient. Therefore, overhauling efficiency of fault equipment can be improved, and operational reliability of a power grid is improved.