The effects of the coherent and incoherent light sources on the resolution of imaging system are studied in the process of non-diffracting beam imaging. In the limited diffraction imaging system, the formula of point spread function (PSF) of the imaging system is derived by the diffraction integral theory and Fourier optical theory. By simulating and comparing the different PSFs, it is found that the PSF is more concentrated and the imaging quality is better under the condition of incoherent light sources. He-Ne laser coherent light with the wavelength of 632.8 nm and incoherent light of blue light LED with the center wavelength of 458.5 nm and full width at half-maximum of 24.5 nm are used for experiment as light source, and Zemax software is used to simulate. Comparing the experimental and the numerical simulation results, the thickness of the stripes image of incoherent source is more uniform, clearer and its resolution is higher. The experimental results are consistent with theoretical analysis and numerical simulation results.