Based on the condition of realizing a fundamental mode and thermal stable cavity, with the help of the computer software, a resonator to realize the fundamental mode and thermal stable output of 447 nm blue lasers is devised. By using the way of high power laser-diode side-pumped, NdYAP crystal as gain medium and choosing class I angle matching LBO and class II angle KTP separately used for second harmonic generation and sum frequency mixing, the fundamental mode and thermal stable output of 447 nm blue lasers is basically realized the acquired continuous stable output is 83.5 mW and the output stability is 1.5%.