In this paper, a novel method of improving coupling effiency of laser diode to single mode fiber based on synthesized lens with graduaed index fiber is provided. The output beam with large astigmatism from laser diode is shaped and focused via synthesized lens and graduaed index fiber, and then couplied into single mode fiber. Analysis using Jones matrix theory indicates that the power coupler effect of 86% is obtained from output port of the single mode fiber. The tolerances for fiber length of graduaed index fiber, radial offset and tilt degree are 60 m, 30 m and 2.4 degree respectivily for 1 dB insert loss. This method can be used for improving the quality of optical beam and increasing output power for laser diode to single mode fiber with a large output optical power.