Abstract: The fluid parameters of tight sandstone reservoir core are studied by using nuclear magnetic resonance (NMR) technology. Principle of nuclear magnetic resonance measuring fluid parameter of tight sandstone reservoir and method of computing the core fluid parameters are described. Experiments to determine the core fluid using T2 cutoff value method, tight sandstone reservoir classification evaluation are researched by using movable fluid. Nuclear magnetic resonance (NMR) measurement of core oil saturation and movable fluid saturation in the oil field, the movable fluid saturation and oil saturation to identify oil and water layer are researched. The result shows that the T2 cutoff value of Honghe oil area is 4.06 ms. By using tight sandstone reservoir core movable fluid level division standard, the tight sandstone reservoir classification evaluation between different layer of single well and multiple well is made. Comparison between Nuclear magnetic resonance (NMR) technology and conventional method of measuring oil saturation in the oil field indicates that nuclear magnetic resonance measurement is feasible and reliable. The value of core oil saturation and movable fluid saturation ratio can identify oil and water layer.