Technology optimization of electro-optical conversion efficiency of crystalline silicon solar cell is introduced. High emitter sheet resistance and how to adapt to the technology of high sheet resistance in following procedures are introduced especially. Considering of technology stability, the method of deep PN junction high sheet resistance is mainly used on the area of high sheet resistance. The open circuit voltage of 635 mV, the short circuit current of 5.817 A and the average cell efficiency of 18.67% have been achieved through a series of technology optimizations and a lot of experiments.