A 0.022 mol fraction doped Cr:LiSAF crystal with 1 mm in thickness is pumped by a 679 nm laser diode, and NCPM KN crystal is used as intracavity doubler. Maximal output of TEMoo 3.15 mW of blue laser at 431.7 nm is obtained with the absorption power of 256 mW. The laser scheme shows a threshold of 96 mW and slope efficiency of 1.97%. Continuous-wave tunable output is demonstrated in the blue region of 423.4～445.5 nm only by changing temperature of KN crystal.