According to the mode field distribution characteristics of semiconductor lasers and single mode fiber, the coupling of the single mode fiber and semiconductor laser is studied by the mode coupling theory, the results show that the fiber end face into a wedge micro lens can make the coupling of fiber and semiconductor laser meet the requirement of the mode field matching and phase matching. Micro lens parameters of wedge type fiber are optimized using the genetic algorithm, the result is that the coupling efficiency achieves the optimum value with wedge-angle of 88°, cylinder lens radius of 3.44 μm and coupling distance of 6.13 μm, the coupling efficiency reaches 88.9% when using the Zemax optical simulation software to simulate the coupling model, the maximum coupling efficiency is 81.36% after laser spot welding and the high and low temperature environment test. The experimental results are similar to the simulation results, the output coupling power can satisfy the demands of seed source power for fiber laser.