The invention discloses a contact debris flow motion parameter monitoring device which comprises a columnar monitoring pile, wherein the lower area of the columnar monitoring pile is fixed in a bed of a debris flow gully, and parameter monitoring sensors are arranged in the upper area of the columnar monitoring pile, and comprise an acceleration sensor, an ultrasonic sludge level sensor and an impact force sensor; the ultrasonic sludge level sensor is arranged above the impact force sensor. The invention further provides a contact debris flow motion parameter monitoring system implemented by the monitoring device. An upper control center of the system communicates with a signal transmission device of the monitoring device through a wireless signal, and the contact debris flow motion parameter monitoring device can be arranged in the debris flow gully in a second-stage or third-stage manner. The invention further provides a debris flow multi-stage early-warning method implemented by the monitoring system. By the device and the system, key power parameters during the real-time monitoring of a debris flow motion process can be comprehensively acquired. According to the method, early-warning accuracy can be improved.