In this paper, the spatial uniformity of natural rainfall is studied by using 10 m×20 m and 10 m×10 m observation networks with a resolution of 1 m. A rainfall test is carried out mainly by using selfmade rainfall cups. The applied mathematical methods include Christianson’s uniform coefficient, distribution uniformity coefficient, rainfall deviation coefficient, rainfall extreme ratio coefficient, and oneway ANOVA. At the same time, the problem of setting the interval of rainfall measuring instrument in dynamic comparison experiment is discussed. The results show that the spatial uniformity of natural rainfall in the observation field is good, and the uniformity index has good consistency; the wind has little effect on the spatial uniformity of rainfall in the observation field, but the difference of rainfall has some effect on the spatial uniformity; the installation interval of rainfall measuring instruments should be less than 5 m in the dynamic comparison experiment, and it is feasible for some smallscale rainfall measuring instruments to set up at a interval of 1 m, such as collecting cups.