Limited by the contrary relationship of the focal depth and the focal size, it is hard to enlarge the fabrication depth while keeping high resolution for laser processing. To solve this problem, a design method for realizing Fresnel lens with long focal depth and small focal size by phase sampling and combination is proposed. A laser processing lens for drilling holes on paper with aperture of 11 mm and center focal length of 47 mm, working at the wavelength of 10.6 m, is designed by using a homemade program. Then it is fabricated and tested. The experiment results show that, compared with traditional lens with the same aperture, this lens has a 2 times longer focal depth, and the focal size is similar to that of the traditional lens along the entire focal depth. This lens is simple to realize and it provides a feasible way to achieve long focal depth and high resolution synchronously. The advantages make it with great application potential in the field of laser processing.