The invention relates to a temperature control device and method based on a TEC. According to the device, a heat radiation fin, TECs, a photoelectric device, a heat transfer plate, a box body, and a constant temperature room are combined. The method comprises the steps that: (S1) a temperature sensor collects the temperature of the heat transfer plate and the temperature of the constant temperature room and transmits temperature signals to a control component, (S2) the control component controls the TECs to carry out heating or cooling according to the temperature signals and controls a heat radiation fan to run or stop, and (S3) the steps (S1) and (S2) are repeated until the temperature of the heat transfer plate collected by the temperature sensor is in an optimal working temperature of the photoelectric device such that the photoelectric device is in a stable and uniform temperature environment. Through designing a closed box body structure, with the constant temperature room as a target control area, with a heat insulating material as a side wall, a constant temperature room structure is designed, thus the photoelectric device is in a constant temperature environment, heat loads are concentrated, the efficiency of temperature control is higher, the precise control of the temperature of the constant temperature room is realized, and a problem that only a local temperature of the photoelectric device meets requirements and an environment temperature does not meet requirements is avoided.