Safety is very important in the dismantlement of screw-joint ammunition parts. The main factor which influences the safety is the temperature of screw area during the process of dismantlement. The design method based on temperature control is studied in the paper. Influential factors including resistant moment, axial force and dismantlement speed are analyzed. The dismantlement speed can be control to satisfy the safety design. The method and steps of the safety design is put forward which aims to control danger limited temperature.