A tunable all-solid-state Nd:YVO4 ring laser, intra-cavity frequency doubled by a type-Ⅰ matched LBO crystal with 671 nm laser output, is demonstrated in this paper. The laser resonator is designed with a four-mirror ring configuration. The YVO4-Nd:YVO4 composite crystal is end-pumped by a 880 nm laser diode (LD). A Faraday optical diode consisted with TGG rotator and half-wave plate is placed inside the resonator for forcing the laser to operate unidirectionally. A solid Fabry-Perot etalon and a piezoelectric-ceramic are inserted into the cavity for tuning the wavelength. The single-frequency output power of 1.08 W at 671 nm is obtained under the pumping power of 23 W (the absorbed pumping power of 14.5 W), the optical-optical conversion efficiency is about 7.4%. With the etalon tuning, a maximal output power of 738 mW is obtained.