Abstract: Carbon tendency controlled by singlefactor method was unstable in theory because the amount of CO was unconstant.According to carburizing devices and technologies of factories,authors solved these problems by using single penetrant,fixing different penetrants,increasing or decreasing the amounts of diluents and enrich agents in proportion and synchronization,and using alcohol as diluent and acetic ether as enrich agents.After these measures had been taken,the qualities of accessories had been greatly improved.