The invention provides a heat dissipation 
system of a 
data center machine room. The heat dissipation 
system comprises heat collection modules, a gas-liquid separator, a 
liquid storage tank, a heat dissipation device and a fluid working medium, wherein the heat collection module, the gas-liquid separator, the 
liquid storage tank and the heat dissipation 
device form a heat dissipation circulating pipeline, the fluid working medium flows in the heat dissipation circulating pipeline, and the collection module comprises an 
evaporation section, a fluid inlet pipeline, a fluid outlet pipeline, a control mechanism, an induction mechanism and a steam 
branch pipeline. According to the invention, the 
data center machine room automatically switches the heat dissipation mode and the working mode to take away the heat generated by the 
evaporation end of the heat collection module according to the 
outdoor temperature condition and the 
thermal load condition of the 
machine room by taking 
energy consumption minimization as a target during operating; the flow is automatically adjusted through the flow self-strain mechanism of the heat collection module so as to solve the problem of heat production difference between the heat collection modules in the cabinet; and the 
refrigeration cycle, the gravity-driven self-cycle and the pump-driven two-phase flow cycle share a radiator array.