High-quality InGaN/GaN multiple quantum wells (MQWs) have been epitaxially grown on La 0.3 Sr 1.7 AlTaO 6 (LSAT) (111) substrates by radio-frequency molecular beam epitaxy. The as-grown InGaN/GaN MQWs are characterized by X-ray technique of high-resolution X-ray diffraction (HRXRD), high-resolution transmission electron microscopy (HRTEM) and photoluminescence (PL) for structural and optical properties. The clear and sharp Pendellösung fringes from the typical HRXRD θ–2θ scan patterns reveal the abrupt InGaN/GaN interfaces and well designed MQWs periodicities, which are confirmed by the HRTEM measurement. A sharp and narrow PL peak of InGaN/GaN MQWs grown on LSAT substrates is observed at 445nm with a full width at half-maximum of 22nm conducted at room temperature, which shows the high optoelectronic properties. This work presents an alternative substrate for achieving high-quality InGaN/GaN MQWs for the potential application of optoelectronic devices.