The invention discloses a thermostatic controller for medical fluid. The thermostatic controller is connected with a transfusion needle by a guide tube with peristaltic pumps and comprises a thermostatic heating system and a thermostatic freezing system. The thermostatic heating system is communicated with the thermostatic freezing system via a fluid channel in a serial connection manner, and comprises a thermostatic heating tank, a first box and a heat-insulation layer, a heating element and a thermostatic heating controller are arranged at the bottom of the first box, one end of the thermostatic heating controller is connected with the heating element, and the other end of the thermostatic heating controller is connected with a power socket; the thermostatic freezing system comprises a thermostatic freezing tank, a second box and another heat-insulation layer, a freezing device and a thermostatic freezing controller are arranged at the bottom of the second box, one end of the thermostatic freezing controller is connected with the freezing device, and the other end of the thermostatic freezing controller is connected with another power socket; both the thermostatic heating controller and the thermostatic freezing controller are connected with external keyboards and external temperature display instruments. The thermostatic controller for the medical fluid has the advantage that the thermostatic controller can be widely applied to medical fluid pipelines with different requirements on temperatures, so that the fluid can be thermostatically utilized at different environmental temperatures.