Semiconductor　laser　is　partially　coherent　beam,　while　the　beam　quality　factor　is　based　on　fully　coherent　beam.　The　Wigner　distribution　function　for　partially　coherent　beam　is　used　to　analyze　the　semiconductor　laser　beam.　The　Wigner　distribution　function　contains　both　spatial　information　and　spatial　frequency　information　in　the　phase　space.　A　method　for　measuring　the　Wigner　distribution　function　of　semiconductor　laser　is　reported.　The　intensity　distribution　of　the　beam　caustics　is　measured　by　two　focusing　mirrors,　and　the　Wigner　distribution　function　of　semiconductor　laser　is　reconstructed.　Based　on　the　reconstructed　Wigner　distribution　function,　the　light　intensity　of　semiconductor　laser　is　simulated.　The　simulated　data　are　in　good　agreement　with　the　experimental　data.　Through　the　properties　of　Wigner　distribution　function,　the　wavefront　aberration　and　coherence　of　semiconductor　laser　are　analyzed.　The　wavefront　of　semiconductor　laser　is　symmetrically　distributed　around　a　point,　and　the　wavefront　on　the　left　side　of　the　laser　diode　array　is　larger　than　that　on　the　right　side.　Due　to　the　temperature　difference　of　the　laser　chip,　the　coherence　on　both　sides　of　the　laser　diode　array　is　better　than　that　in　the　middle　of　the　laser　diode　array.