The invention provides a modulation-based biological motion sensed brain-machine interface method. The method comprises the following steps: firstly, carrying out modulation-based biological motion normalise design and implementation; secondly, constructing a brain-machine interface platform; and finally, processing brain electrical signals and identifying targets. Visual stimulation is carried out on the basis of signal modulation, the number of the targets is increased in limited frequency by frequency modulation, the problem that stimulation frequency of a traditional evoked potential brain-machine interface based on steady vision is solved effectively, effective stimulation of low-frequency biological motion is realized by high-frequency flickering and low-frequency motion, low-frequency biological motion information which cannot be identified is modulated to a side band of high-frequency signals through a modulation effect, by high flickering frequency and sum frequency and difference frequency feature recognition of the high flickering frequency and low motion frequency, low-frequency biological motion is identified effectively, a usable frequency range of the brain-machine interface can be effectively extended, and a foundation is laid for a same-frequency stimulated brain-controlled lower limb rehabilitation and training system.