The invention belongs to the technical field of preparation of neoprene rubber. In order to solve the problems that the conventional sulfur-modified neoprene rubber has an unstable final chain scission product and poor raw rubber storage stability, and after long-time storage, the hardness is increased, the plasticity is decreased, and the processability and the performance are reduced, a preparation method of later chain scission-free sulfur-modified neoprene rubber is provided. The preparation method comprises the following steps: dissolving sulfur and stearic acid into a chloroprene monomerto obtain an oil phase, mixing strong alkali, formaldehyde condensation sodium beta-naphthalenesulfonate, sodium rosinate soap and TP to obtain an aqueous phase, emulsifying the oil phase and the aqueous phase, performing a polymerization reaction, adding a terminating agent for terminating the reaction after the specific gravity reaches a certain value, adjusting the pH value by using acetic acid, freezing, washing by using water, and drying to obtain dry rubber. An appropriate Mooney viscosity value can be obtained without further chain scission; the latex performance is stable, and after acertain period of storage, the Mooney viscosity is stable and the other performance is not affected; in an experimental process, the dissolution time and the previous preparation time of raw materials are shortened and the polymerization efficiency is improved; through addition of novel primary and secondary antioxidants, post-processing and utilization of the rubber are facilitated.