In this paper, a kind of hybrid light trapping structures in thin film crystalline silicon solar cells, combined of dielectric nanoparticles on the front and metal nanoparticles on the rear, was reported. Numerical simulations were performed based on the finite-difference time-domain solutions, and the wavelength ranges that the dielectric nanoparticles and metal nanoparticles had impact on, were systematically analyzed. The absorption enhancement mechanisms were shown through the electric filed figures, including the scattering of these two kinds of nanoparticles, and the near field enhancement of surface plasmons excited by the metal nanoparticles. Simulation-based optimizations of the periods and sizes of Ag, TiO2 etc nanoparticles were given. Furthermore, a 30.3% increase in the short circuit current density was obtained in a solar cell with the optimized hybrid light trapping structure. This structure, combined of the different nanoparticles with different locations, is a new way to improve the conversion efficiency of thin film solar cells.