We report a high-power diode-end-pumped Q-switched Nd:GdVO4 red laser through intracavity frequency-doubling with a type-I critical phase-matched LBO crystal. The maximum average output power at 671 nm was obtained to be 6 W at the repetition frequency of 47 kHz, with the corresponding optical conversion efficiency of 12.8% and the pulse width of about 97 ns. At the average output power around 5 W, the power stability was better than 5.8% for one hour.