Based on improvement and optimization of fermentation process of cephalosporin C and expansion of its production scale，with reference to the mature fermentation liquid culture technology of penicillin，the low unit fermented liquid in fermentation process of cephalosporin C was collected for training again. The results showed that adopting the process，the production could be increased 374.5 Ka every day and the cost of raw materials was reduced more than a half，the quality indicator DOCPC of fermentation liquid after re-training was reduced from 0.6 to 0.3.The implementation of this process could increase the cephalosporin production, reduce the cost of raw materials, improve the quality of the fermented liquid, reduce the COD emissions.