A modulized heat-dissipation control method for a datacenter is provided. In this method, a temperature sensor is used to sense inner temperatures of multiple servers and CPU temperatures in the multiple servers. If any one of the CPU temperatures is abnormal, a flow of a first coolant is adjusted. If any one of the inner temperatures is abnormal, a rotating speed of a fan module is adjusted. If the rotating speed of the fan module has reached its maximum, a flow of a second coolant is adjusted.