The　high　peak　power　of　picosecond　pulses　produced　by　a　self-mode-locked　semiconductor　disk　laser　can　effectively　improve　the　efficiency　of　nonlinear　frequency　conversion.　This　paper　presents　the　intracavity　frequency　tripling　in　a　self-mode-locked　semiconductor　disk　laser,　and　a　picosecond　pulse　train　at　327　nm　wavelength　is　achieved.　The　pulse　repetition　rate　is　0.49　GHz,　and　the　pulse　width　is　5.0　ps.　The　obtained　maximum　ultraviolet　output　power　under　mode　locking　is　30.5　mW,　and　the　corresponding　conversion　efficiency　is　obviously　larger　than　that　of　continuous-wave　operation.　These　ultraviolet　picosecond　pulses　have　high　spatial　and　temporal　resolution　and　can　be　applied　in　some　emerging　fields.