The invention provides a self-frequency doubling laser with function of single beam laser output or linear laser output. The self-frequency doubling laser comprises pumping sources, an optical crystal, laser resonators and crystal cooling and temperature control devices with functions of heat dissipation and temperature control, wherein the two end faces of a slab of the self-frequency doubling crystal are optically polished and plated with high fundamental frequency laser and frequency doubling laser transmissive films; one surface of the slab-shaped self-frequency doubling crystal is placedon the first crystal cooling and temperature control device; the pumping sources at least aim at one surface of the self-frequency doubling crystal and enter; high pump light transmissive films are plated on the parts where the pump light enters; the pump light carries out pumping and is fully absorbed; and the fundamental frequency laser and the frequency doubling laser are ensured to be propagated in the crystal in the shape like a Chinese character yi or zhi, thus implementing single beam laser output or linear laser output. The laser provided by the invention has the following advantages:enlarging the effective cooling area of the crystal, being beneficial to efficient heat dissipation and accurate temperature control of the crystal, reducing the internal heat gradient of the crystaland ensuring the frequency doubling process to better meet the phase matching requirement. Besides, the laser can implement single beam laser output or linear laser output.