The invention discloses a calculation method for the detection efficiency of a thunder positioning system. The method comprises the following steps that S1) a lightning current amplitude is divided into multiple sections, and the detection efficiency of one detection station in the thunder positioning system is calculated from each amplitude section; S2) an evaluated area is divided into multipledetermination areas, and the thunder detection efficiency of each amplitude section in each determination area is calculated; and S3) the total thunder detection efficiency of all the determination areas is calculated. Thus, the detection efficiency of the thunder positioning system can be reflected more vividly, and the operation performance of the determination area can be evaluated more accurately.