利用地球磁场核磁共振(EF NMR)的方法测量水中质子自旋弛豫的时间.两种不同的自旋弛豫时间T1 和T2 分别测得为(2.46±0.16)s 和(0.83±0.02)s，与《Measurement Science and Technology》2012 年(21 卷)第10 期上Michal CA 一文所得到的结果T1 = 2.3±0.1 s 吻合较好.此外，实验数据也验证了居里定律，并通过对硫酸铜溶液的测量说明了溶液中离子的存在会使自旋弛豫过程加快.此工作提供了一种利用地球磁场测量秒量级的自旋弛豫时间的方法.

Earth′s field nuclear magnetic resonance (EF NMR)approach is used to study the spin relaxation process of protons in water. Two different spin relaxation times，T1 and T2，are measured to be (2.46±0.16)s and (0.83±0.02)s，which are in well agreement with the results T1 = 2.3±0.1 s from the reference [1]. Besides，the experimental results also confirm the Curie Law. The measurements on copper sulphate solution imply that the existence of ions in solution will accelerate the spin relaxation process. This work provides a way to study spin relaxation process in seconds scale by EF NMR.