In this paper, we investigate spatial dark solitons in nonlocal nonlinear media. Based on the nonlocal nonlinear Schrödinger equation and the diffusion equation, the numerical solutions with different propagation constants are obtained by using the Newton iterative method. And it is found that there exist dark soliton solutions .and the relation between the width of dark soliton and the degree of nonlocality for any propagation constant under arbitrary nonlocal degrees different propagation constants. In experiments, we observe the formation of the spatial dark solitons in the solution of dye. The influence of Gaussian background on dark solitons is also discussed, and the numerical results are in agreement with the experimental results.