532 nm green laser with an average power of 63 W based on an intracavity-frequency-doubled lamp-pumped acousto-optic(A-O) Q-switched Nd∶YAG laser is reported. The structure of dual-lamp-pumped gold-plated metal cavity, pumping uniformity and the cooling uniformity and reliability of KTP frequency-doubled crystal are analyzed and a highly reliable set for cooling frequency-doubled crystal is developed. The optimum geometric cavity length of 549 mm is got through studying the influence of the frequency of A-O modulator and the temperature of frequency-doubled crystal on the output power of frequency-doubled laser with L-shaped cavity. When the pumping power is 4.9 kW and A-O modulating frequency is 4 kHz, the 532nm output power is 44 W with the pulse width of 80 ns; When the A-O modulating frequency is 10 kHz, the 532 nm output power is 63 W with the pulse width of 140 ns, frequency-doubled efficiency is 64%, total electrical-optics efficiency is 1.2% and beam quality is M2=11.1.