The invention discloses a temperature sensor dynamic response calibration device and a step time measurement method. The device comprises a constant-temperature constant-speed water trough, a supporting frame, a mechanical arm and a data recorder, wherein the supporting frame is installed above the constant-temperature constant-speed water trough in a sleeving mode, and the mechanical arm is installed on the supporting frame; a temperature sensor is installed at the bottom end of the mechanical arm and is connected with the data recorder through an outgoing line; the constant-temperature constant-speed water trough comprises a rotating cylinder and a stationary cylinder, wherein the rotating cylinder is installed outside the stationary cylinder in a sleeving mode; and the data recorder isprovided with a first wire, a second wire, a third wire and a fourth wire, wherein the first wire is arranged in the constant-temperature constant-speed water trough, the second wire is connected withthe temperature sensor, the third wire is connected with the supporting frame, and the fourth wire is connected with the mechanical arm. Through the device and the method, dynamic response calibration can be performed on the temperature sensor, step temperature generation time can be accurately measured, the relation between the temperature step time and a sensor time constant can be judged, andit is guaranteed that a calibration result is effective.