In this paper, the ghost plating problems of crystalline silicon solar cells is studied in theory and experiment. After laser doping process, a pretreatment process is needed to remove SiO2 in the heavy doping area and keep SiN mask simultaneously by using chemical solution containing HF. Otherwise, the unexpected non-heavy-doping area would be plated with silver, resulting in the ghost plating problems. The mechanism of HF etching SiO2 and SiN is analyzed and the feasibility of selective etching is discussed. By changing the main aspects of affecting the etching rate, the ghost plating of crystalline silicon solar cells is improved.