Abstract: Steam-water separation equipment, as one of the main components of steam generator, affects steam generator hydraulic recirculation performance as well as water level adaption, determines the size of steam generator upper shell and assures stable operation of steam turbine. Hot rig tests of CAP1400 steam generator steam-water separation equipment were conducted under various steam loads, saturated water flow rates, normal and high water levels. Separation characteristics of SP3 primary separator and P3X dryer varying to steam load, saturated water flow rate and water level were obtained. Resistance characteristics of primary separator and dryer were obtained respectively by measuring resistance. The test results lay a foundation for the research and development of the CAP1400 steam generator.