The invention discloses an ultrasonic excited top coal caving device used cooperated with a hydraulic support, and an application method thereof. The device and the method are mainly used to solve a problem that high-intensity and good-integrity hard coal seams are difficult in top coal caving. The invention belongs to the technical field of coal mining. The device is formed by an ultrasonic excitation system, an elevating servo system, an optical probe, and a data process system. The ultrasonic excitation system is formed by an ultrasonic generator and transducer, etc. The elevating servo system is formed by a hydraulic transmission system and a lifting rod. The optical probe monitors top coal breaking degree. The data process system is used to acquire monitored data of the optical probeand control the elevating servo system to change height of the transducer. The device is arranged in a top beam groove of a hydraulic support, and the transducer and the top coal are controlled to beeffectively abutted, and ultrasonic excitation is applied to make top coal have cracks, to achieve objectives of weakening top coal and improving top coal cavability. The device is simple and practical, safe and reliable, and is high in automation degree and good in effect.