The invention provides a multidimensional nuclear magnetic resonance method for measuring the pore size and the pore surface relaxivity of a rock. The method includes the steps of data acquisition, data extraction, data processing and data interpretation. The method is characterized in that a sample is excited and measured by using a new pulse sequence to simultaneously obtain the pore size a of the rock and the pore surface relaxivity rho1 of the rock. The method achieves the simultaneous measurement of the pore size and the pore surface relaxivity of the rock for the first time, and is suitable for nuclear magnetic resonance detectors under different field intensities, so the method is important for obtaining important physical parameters of the rock in core analysis in the prior art.