An experimental research of laser diode （LD）end-pumped crystal component Nd∶YVO4+KTP is reported.In the case of without inserting any frequency selector,the 532 nm single frequency laser output is obtained.Considering the nonlinear spectral bandwidth,gain bandwidth and nonlinear conversion efficiency,the nonlinear loss of the non-oscillating modes that in the range of nonlinear spectral bandwidth will be increased via the SFG（sum-frequency generation）process,which prevent them from oscillating.Based on this theory,with 900 mA LD working current,66 mW single frequency 532 nm laser is obtained.Stability is better than 0.99%.The experimental results show that this structure type of laser provides an effective method for high stability and low-cost single frequency lasers.