Larvae of the serious agricultural pest Pieris rapae and its closely related species Pieris canidia mainly harm a variety of Brassicaceae vegetables and oil crops, posing a major threat to agricultural food security. In this study, a total of 248393 occurrence data were collected, among which 361 were collected by field investigation. Based on these occurrence data, six species distribution model algorithms were used to predict the global potential distribution areas of the two species under historical, current and future climate conditions. The results showed that: (1) among the model prediction results of 13 algorithms based on 6 climate variables after removing spatial autocorrelation, the values of 6 model evaluation indicators were higher than the random state (0.5). (2) Under the current climate conditions, the potential distribution areas of P. rapae mainly included North America, southern South America, western Europe, southeast China and southern Australia; P. canidia was mainly distributed in northern South America and southern Asia. Compared with P. canidia, the potential distribution area of P. rapae in the three periods was larger, but the potential distribution area of P. canidia would increase in the future, with a higher potential invasion probability. (3) Compared with the invasive species, P. rapae, its closely related species, P. canidia, had a better capacity to adapt to the hot and rainy climate. Faced with the trend of global warming in the future, P. canidia is likely to become an invasive species. Therefore, it is necessary to strengthen pest monitoring, prevention and control forecasting for its potential distribution areas under future climate conditions. This study predicted and compared the potential distribution areas of the two species under different climatic conditions, and provided a theoretical basis for the control of these two serious agricultural pests.