The present invention provides a method and system for testing oil-water capillary pressure curves of dense cores, comprising: a magnet, a gradient coil, a sample moving platform, a nuclear magnetic resonance radio frequency coil, a nuclear magnetic resonance spectrometer, a radio frequency power amplifier, a gradient amplifier, a power supply, a water cooling machine, a computer including a host and a display, and a preamplifier; the gradient coil is equipped with a water cooling system; by designing a pure phase encoding pulse sequence with a shorter echo time, the fast decaying signal in the dense core is collected, and the fluid saturation distribution when the oil and water phases coexist in the dense core is obtained in combination with a centrifugal device, which is used to test the oil-water capillary pressure curve of the dense core and is more suitable for use at oilfield development sites.