Abstract: A high stability and compact structure 488 nm light generated by intra-cavity frequency doubling in an optically pumped semiconductor disc laser was designed. In order to obtain a 488 nm laser with good beam quality and stable performance output, a semiconductor gain medium chip with 13 QWs and 808 nm/976 nm Double Band Mirror was pumped vertically by 808 nm LD on the top surface of the chip, and the chip with double diamond heat spreaders bonded on the both sides was introduced. 488 nm laser was generated by doubling frequency with I phase matched LBO crystals inserted in the cavity. 111 mW 488 nm laser with 1.3 nm spectral line width was obtained, the optical to optical efficiency was 1.2%, the beam quality of Mx2、My2 were 1.03 and 1.02 respectively, and the instability is less than 0.6% with continuously work for more than 3 h.