In order to ensure the independence of every sampling, ghost imaging system with repeatable pseudothermal light based on random phase plate moves one laser spot in each sampling to produce pseudo-thermal light. By using rotating motor and linear motor to control motion trail of random phase plate, an experimental platform is established. Based on differential ghost imaging linear reconstruction algorithm and nonlinear sparsity constraints reconstruction algorithm, the influence of different offset value Δx of the random phase plate on the quality of ghost imaging is studied researched. The results of the simulation and experimental results demonstrate that in the case of the same compression ratio, when Δx is no more than the speckle size Δxs , the imaging quality enhances with increasing Δx , and when Δx is larger than Δxs , the imaging quality almost does not change with increasing Δx. Besides, in the case of the same sampling, the imaging quality by using nonlinear sparsity constraints reconstruction algorithm is better than that by using differential ghost imaging linear reconstruction algorithm.