A widely tunable 4.16–7.31 μm high-resolution mid-infrared optical parametric oscillator with a type-I BaGa₄Se₇ (BGSe) crystal pumped by a 1064 nm laser was demonstrated for the first time. We have achieved a wavelength tuning accuracy of less than 5 nm through simultaneously performing temperature tuning and angular tuning on the BGSe (46°, 0°) Optical Parametric Oscillation (OPO). The wavelength resolution will be less than 1 nm when using commercial temperature control equipment.