The invention discloses a tunable plasmon tweezers device, a plasmon tweezers system and a plasmon tweezers operation method thereof based on terahertz waveband, wherein in the tunable plasmon tweezers device, a middle layer is laminated on a base layer, and an upper layer is laminated on the middle layer and comprises periodic groove arrays; the plasmon tweezers system comprises a terahertz generation module, a transmission and focusing module, a capturing and observing module and a detection and post-processing module; the plasmon tweezers operation method comprises the following steps of radiating terahertz electromagnetic waves to the tunable plasmonic tweezers device, wherein geometries and/or sizes of grooves enable the terahertz electromagnetic waves to be locally focused inside thegrooves to form three-dimensional potential well forces inside the grooves, and an object to be captured is captured in the grooves through the three-dimensional potential well forces.