With the purpose of distinguishing and revising the abnormal values of lightning location data and improving the accuracy of lightning location products, this study uses such methods as the Tyson polygon, the hypothesis test of data distribution, abnormal values (with the FiveNumber Summary) to establish a technique that associates with the manual observation of lightning days to distinguish the abnormal grid data of lightning density location on the lightning positioning gird density map. The application case of Fujian Province is discussed. The results show that there are certain detection errors or data loss of lightning location data in the northern and western parts of Fujian Province; the correction is conducted in the areas with unusual values by the artificial observation of lightning data; the method can be used in the areas with less lightning location instruments to distinguishes and optimizes the abnormal values of lightning location data.