The experimental results of high-power red laser constituted of a symmetrical linear resonator with two pumping modules, and intracavity frequency-doubling with a KTP crystal are reported. The average output power of 83 W at 659.5 nm was obtained in the condition of 1250 W pump power and the acoustic-optical Q-switching repetition rate of 10 kHz. The optical-optical efficiency was 6.5% and the optical slope efficiency was 17%. The laser adopted a plane-plane cavity structure. Every pumping head was equipped with a high power continuous wave (CW) side-pump module comprising of a Nd:YAG rod side-pumped by thirty-five 20 W laser diode arrays (LSAs) with pentagon geometry. To realize the oscillation of single wavelength of 1319 nm in Nd:YAG, the reflectivities of the resonator mirror are designed, which also leads to the single wavelength output of second-order harmonic (659.5 nm). The laser output characteristics of fundamental and frequency-doubled wavelengths have been studied.