The structure model and structure characteristics of sulfur donor N,N’-dithiodimorpholine were introduced. The dosage of DTDM influencing on the heat-resistance of vulcanized rubber, and vulcanization character at high temperature, vulcanization availability, selectivity to metal oxide and toxicity prevention of DTDM were analyzed. When adding compound capable of absorbing free morpholinyl group in sizing material, the content of toxic morpholinyl nitrite would be reduced 95%.