The surface texturing of multi-crystalline silicon is a technology that needs to be broken through. For the improvement of pit-trap shape on mc-Si surface, a new method is presented that the passiviation of Si surface is done to reduce the acid reaction velocity. A series of experiments are carried out in which mc-Si is textured in the acid solution containing different content of additives under the same technology parameters. Samples′ structure is observed using scanning electron microscope, and the reflectance spectrum is measured by spectrophotometer. The SEM of experimental sample′s surface illustrates that the textured surface is full of a lot of pit trap with the good light trapping effect. Moreover, the deep ditch like valley, which increases the leakage current of mc-Si solar cells and reduces the conversion efficiency, is not found in the surface. This method is valuable for the improvement of solar cell efficiency.