The scientific use of hybrid feedback is the focus of German academic writing teaching and research in the new era. This study constructs a hybrid model of German academic writing through the organic integration of teacher feedback, peer feedback and AI feedback, and discusses the AI chatbot. The teaching experiment was designed with a university’s senior non-German majors as the research subjects, and the German academic writing achievement scores of the students in the mixed feedback group gained a significant improvement after the experiment (14.40%, P < 0.01), and there was a significant difference with the other three single-feedback groups. On the other hand, the mixed feedback group improved 20.98% and 33.32% in writing fluency and writing accuracy, respectively, and the students’ planning ability, self-monitoring ability, task evaluation ability, illustrative-narrative ability, self-correction ability, and self-assessment ability also increased significantly compared with those before the experiment. The results show that the mixed feedback model helps to improve learners’ writing performance, writing fluency and accuracy, and promotes learners’ German academic writing ability.