1937年7月7日卢沟桥事变,日军开始大规模侵略中国,当时中国空军还处于初建阶段,航空业刚刚起步,兵力十分薄弱。中国空军的大部分飞机是从美、意、德、英、法等国进口。根据国民党政府的资料,与日军交战时,国民党空军共有各型飞机600余架,其中305架为作战飞机,这些飞机中大多数从外国进口。当时的中国轰炸航空兵还处在萌芽时期。 July 7, 1937 Marco Polo Bridge Incident, the Japanese aggression began massive invasion of China, when the Chinese Air Force is still in the early stages of construction, the aviation industry has just started, the force is very weak. Most of the PLAAF aircraft are imported from the United States, Italy, Germany, Britain and France. According to the KMT government's information, when fighting Japan, the Kuomintang Air Forces had more than 600 aircraft of various types, of which 305 were combat aircraft, most of which were imported from foreign countries. The then Chinese bombing aviation was still in its infancy.