A device capable of simultaneous independent motion measurement of multiple probes in an atomic force microscope includes at least two cantilever arms arranged in parallel. The end of each cantilever arm is provided with a needle tip. The surface of each cantilever arm is provided with a grating structure with a periodic distribution rule for reflecting laser irradiated on the grating structure and receiving the laser through reflected light detectors. The discrimination and motion measurement includes the steps of irradiating the measurement laser of different wavelengths on the back surfaces of multiple probes through the same light path at the same time, adopting the grating structures of different feature sizes as physical labels of the multiple probes and reflecting high-order reflected light of the laser of different wavelengths by the grating structures at different angles to separate the light path.