A non-contact muscle signal sensing and assisting device, comprises a radar sensing module, a microprocessor and an electrical stimulation module. The radar sensing module continuously transmits a first microwave signal to a muscle bundle part and receives a corresponding reflected muscle signal, and performs a demodulation procedure on a second microwave signal and the reflected muscle signal to obtain and output a demodulated muscle signal. The microprocessor performs a muscle-movement signal characteristic processing procedure on the demodulated muscle signal to obtain a characterized muscle signal. The microprocessor obtains a muscle movement parameter according to the characterized muscle signal and controls the electrical stimulation module to emit a micro electrical stimulation signal to stimulate a reflex nerve when the muscle movement parameter fits an assistive condition, thereby stimulate muscle movement.