In this paper, a structure of embedding metal nanoparticles in the Si layer of a crystalline silicon thin film solar cell is proposed. By controlling the shape, material and spacing of the metal nanoparticles, the LSPR effect excited by the metalnanoparticles surface is used to improve the absorption of light of crystalline silicon thin film solar cell. The micro-nano optical simulation software (FDTD) was used to simulate the Si layer absorption rate and photogenerated electron rate under different conditions. Compared with thin-film solar cells without embedded nanoparticles, when embedded in spherical Ag nanoparticles, the Si layer absorption rate is significantly improved in the range of 0.8~1.1μm, the overall absorption rate is increased by 23.1%, and the photogenerated electron density is significantly elevated around the nanoparticles. When embedded in the four nanoparticles of Ag, Au, Cu, and Al, the absorption rate curve fluctuates in the range of 0.45~1.1μm, and the absorption peaks in a wider range can be excited when the Al nanoparticles are embedded. Moreover, the overall distribution of the photogenerated electron density of the Si layer is best in the presence of Al nanoparticles. In the analysis of two Al nanoparticle spacings T of 0.1μm, 0.15μm and 0.2μm, the absorption rate was better when T was 0.1μm in the range of 0.45~0.75μm. When T=0.15μm, a wider absorption peak is excited than the other two cases near the 0.9μm and 1.0μm, and the overall photogenerated electron density is higher in the upper region of the Si layer.