Abstract: The outbreak of floods in Tianjin in 1939 not only caused a series of negative impacts on Tianjin, but also brought certain influence to Peiping. This was due to the special geo-relations between Peiping and Tianjin and the resulting "lip-tooth dependence". In response to this impact, the Japanese puppet regime of Peiping took a series of the initiatives to offer assistance to Tianjin in settling refugees, raising disaster funds, releasing relief supplies and organizing medical teams in the names of " helping each other" and "fighting for the neighbors". The disaster relief activity in Peiping was considered as an important part of Tianjin disaster relief activities, which, from an objective view, did alleviate the impact of the floods on Tianjin. On the one hand, the appearance of such phenomena showed the relationship between the two cities in terms of suffering and sharing; on the other hand, it also showed that the two cities had established synchronization and coordination to some degree in dealing with natural disasters. For all that, under the background of the invasion of the Japanese puppet government, the disaster relief activities in Peiping had characteristics of concealment and deception. It aimed at shaping the illusion of "pro-ministry" and " goodwill between China and Japan" of the Japanese puppet regime and had the purpose of annihilating the Chinese people's sense of nationality and resistance. To a certain extent, it also determined the nature of the Peiping-Tianjin relationships.