An average 104 W green beam operation by intracavity frequency doubling of Nd:YAG laser, which is pumped by eighty 20 W high-power laser diodes is reported. A type Ⅱ phase matched KTP crystal (=23.6°,θ=90° under the condition of 27 ℃，its size is 7 mm×7 mm×10 mm) is applied for frequency doubling of Nd∶YAG laser. The length of resonator is 530 mm. The KTP crystal is placed in the special cooling device. Under the pumping current of 18.3 A, KTP crystal is cooled to 4.5 ℃. A maximum green power of 104 W was generated at 20.7 kHz repetition rate and 132 ns pulse width when pumping current of laser diodes is 18.3 A, leading to 10.2% of optical-optical conversion efficiency.