Photon sieve is a new type of diffraction element, which is not limited by diffraction limit and has flexible design structure. Compared with amplitude-type photon sieve, phase-type photon sieve has higher energy transmittance and sharper imaging contrast, which has application advantages. However, common diffractive optical devices face limitations of complex processing and difficulty in tuning. Graphene and its derivatives have good photoelectric tuning properties and are widely used in the preparation of diffractive optical devices. Laser direct writing technology can realize the induced reduction of graphene oxide, which is a simple and efficient micro-nano processing technology. In this paper, the diffraction characteristics of the photon sieve is studied by using the finite-difference time-domain method, and the graphene oxide photon sieve is prepared based on the laser direct writing technology. The refractive index modulation of the material can be obtained by processing with different laser power, and the device can achieve obvious focal length modulation (1.62 mm) and focus efficiency improvement (13.6%). This method is expected to provide a simple and flexible design and preparation method for realizing tunable diffractive optical elements.