In this paper, we investigate the interactions between optical spatial solitons in nematic liquid crystals (NLC) with numerical simulations and experiments. The response function is exponential-decay function in NLC, which is different from the Snyder-Mitchell model. Through numerical simulations, we discovered that the crosspoint of soliton interaction is in inverse proportion to the square root of injection power in NLC . We also found that the position of crosspoint is independent of the distance between solitons in strong nonlocal Gauss function response, but it is not the same with exponential-decay function in NLC. Through experiments,we found the positions of crosspoint is in inverse proportion to the square root of inject power,it is also related to the critical power of solition formation and the distance between solitons.