The propagation of nonlocal spatial solitons in nematic liquid crystals is studied experimentally. On the basis of propagation equation of nonlinear nematic liquid crystals solitons, we obtain the analytical solution of solitons by using Gaussian trial solution and compare our model with Snyder's strong nonlocal solitons model. In experiment, we observe the propagation of solitons in nematic liquid crystals, and determine the critical power of optical spatial solition in different beam width, for example, when the beam width is 2 μm, the critical power is 2.0 mW. The relaxation process of optical solitons in nematic liquid crystals is discovered and it is noticed that the molecule of nematic liquid crystals takes several seconds to respond, and the generation of optical solition is not fast.