Abstract: To establish a new model of maize inbred lines planting three generations in one year, research methods such as the greenhouse and field trials were utilized, generation adding planting and breeding were studied. The results showed that: the three generations in one year planting and breeding model of maize inbred lines that planting in greenhouse of Shandong in spring, seeding in Shandong in summer and dreeding in Hainan in winter was reliable and the maneuverability was strong, which expanded the scope of breeding through breeding of maize inbred line under different environmental conditions. Using this adding generation model, maize inbred lines were planted on around February 25 in the greenhouse of Shandong in spring, pollinated around May 1, and harvested around June 12, the filling stage was more than 42 days and the kernels were almost full; planted on around June 15 in summer and harvested around October 5, timely dried and tested; planted on around November 8 in Hainan in winter, harvested around February 20, dried for 3 days and then the kernels were transported back to Shandong for planting in greenhouse, thus, three generations in one year was finished. The characters of maize inbred lines bred by this model were reliable and could be used in production.