1931年,由于国民政府采取“攘外必先安内”的政策,东北军执行不抵抗命令,致使日军迅速占领东三省,华北门户洞开,冀察两省和平津两市直接暴露在日军的刺刀之下,随时面临被侵占的危险。1933年5月,长城抗战失败后,国民政府与日本签订了《塘沽协议》、《何梅协 In 1931, due to the Nationalist government’s policy of “settling the enemy outside the borders,” the Northeast Army did not resist the order. As a result, the Japanese army quickly occupied the northeastern provinces of Northeast China and opened their doors to northern China. The two cities of Hebei and Pingjin were directly exposed to the Japanese troops Under the bayonet, at any time facing the danger of being invaded. In May 1933, after the failure of the Great Wall Anti-Japanese War, the National Government signed a “Tanggu Agreement” with Japan and the "He Mei Association