To improve the decoding speed and performance of Weighted Bit Flipping (WBF) decoding algorithm for Low Density Parity Check (LDPC) codes, a two-stage WBF algorithm with a multi-/single-bit switching mechanism is proposed. It first performs multi-bit flipping decoding in the first-stage decoder. When cyclic flipping is detected or the maximum flipping function value is less than zero, it switches to the second-stage decoder. Simulation results show that the proposed algorithm obtains gains both in average decoding iteration number and in decoding performance compared with the Sum of the Magnitude based WBF (SMWBF) and the Variable node updating based SMWBF (VSMWBF).