In diode pumped Nd:YAG lasers, the quantum defect is the most important parameter determining the thermal load of the laser crystal, which can be dramatically reduced by pumping directly into the upper laser level. A compact folded three-mirror cavity with a length of 105 mm is optimized to obtain a highly effcient 473-nm laser. When the absorbed pump power (with 15.8-W incident pump power) at 885 nm into Nd:YAG is 10 W, a continuous-wave 473-nm blue laser as high as 2.34 W is achieved by LBO intra-cavity frequency doubled. The optical-to-optical conversion effciency is 14.8%. To the best of our knowledge, this is the highest e±ciency at 473 nm by an intra-cavity doubled frequency Nd:YAG laser.