The invention discloses a redrying and mellowing method for reducing the crotonaldehyde release amount. The method includes a tobacco flake redrying process and a mellowing process. The mellowing process includes the step of adding mellowing agents in redried tobacco flakes, wherein the mellowing agents are biological agent aqueous solutions, and biological agents are one type or multiple types of bacillus subtilis, bacillus megatherium, bacillus circulans, bacillus amyloliquefaciens bacillus freeze-dried powder. According to the method, the biological agents are added as the mellowing agents, degradation and conversion of crotonaldehyde in tobacco raw materials can be effectively promoted in the tobacco mellowing process, the process of reducing the crotonaldehyde release amount in cigarette smoke is carried out before the tobacco threshing, redrying and mellowing stages, and the method has important theoretical significance and practical application value by combining the tobacco threshing and redrying process and the mellowing process.