The invention discloses a machine tool transmission chain detection device. The device comprises a knife bar angle displacement sensor and a workbench angle displacement sensor. The knife bar angle displacement sensor and the workbench angle displacement sensor are connected to a rotational transmission precision measuring instrument. A stator of the workbench angle displacement sensor is embedded and fixed into a center hole of a disk-shaped leaf spring and the stator and the center hole are concentric. An edge portion of the leaf spring is fixed to a machine body of a machine tool through a magnetic stand. The workbench angle displacement sensor is supported by a sensor pedestal and a rotor and a machine tool workbench are coaxially rotated and connected. The invention also discloses a machine tool transmission chain detection method. The device and the method have advantages that 1, a problem that an installation and positioning position of the stator of the workbench angle displacement sensor on the machine tool, which accords with a requirement, is difficult to find is solved, damages of a tooling used for fixing the stator to the machine tool are avoided and installation time is shortened; and 2, a problem that the stator needs to be repeatedly dismounted and clamped before measurement when the angle displacement sensor repeatedly carries out transposition and measurement is solved, and measurement precision and operation convenience are increased.