The invention belongs to the technical field of automatic control of thermal generator sets, and particularly relates to a checking method for preventing failure of a thermal process protection system of a thermal generator set. The thermal process protection system comprises the following elements: design of the logic of a main protection system of the set, design of an important auxiliary engine protection system of the set, measuring and sampling by an instrument, and allocation of DCS hardware addresses; the inspection method comprises the following steps: collecting the design data of the thermal process protection system, and knowing the composition condition, the operation mode and the operation parameters of the thermal process protection system of the thermal generator set; checking the thermal process protection system of the thermal generator set by referencing to the latest national electric power industry regulations and specifications, and finding design defects and potential safety hazards; proposing a regulating solution for on-site regulation, finishing a static test and a dynamic test, and putting the thermal generator set into safe operation; and if the requirements are not met, returning to the regulation and test steps till meeting the requirement. The checking method has the advantages that the checking steps are simple and clear, the safety and the reliability are realized, the on-site debugging process is simple, and the operation and the implementation are convenient.