Abstract: A parameter optimization system is established for X-ray in-line phase contrast imaging of the object of two dimensional Gaussian distribution based on the theoretical analysis of the imaging technology. The dependence of the evaluation parameters including contrast, signal-to-noise ratio, resolution and sampling on the systematic parameters including X-ray energy, source size, detector resolution, imaging geometry and sample properties is clarified. The systematic parameters of the imaging systems under the irradiation of sub-micron focus X-ray source, laser-driven micro-focus X-ray source and synchrotron radiation X-ray source are optimized, respectively, by the means of numerical simulation. The outcome shows that the optimization system completes the optimization task very well.