Abstarct: This dissertation presents the design and simulation of X-ray radiographic system with a slit scanning technique using the powerful multipurpose GATE Monte Carlo code. Different phantoms can be defined with the help of this code. In this study, the geometry of the source to the detector and the position of the object are defined for the slit scanning imaging system, and an X-ray imaging system is simulated by scanning the whole body baxsed on the parameters in the imaging chain. The following describes the applications of the simulation system for reducing scattered beams and filtering. In this study, the effects of parallel gap width on image quality and patient absorption dose were simultaneously assessed. In order to evaluate the image quality, object tests were designed and used to determine the standard criteria of image quality, namely contrast test and contrast ratio to noise, MTF, NPS and DQE, and Zubal anthropomoprphic phantom to evaluate and estimate patient absorption. In order to optimize the reduction of the absorbed dose while maintaining the image quality of the slit scanning system, the effect of different filtration thicknesses on the beam between the source and the body has been studied. Also, in order to reduce voltage fluctuations on the beam quality, the effect of voltage ripple caused by different generators used in clinical radiography in the range of diagnostic energies was evaluated. The simulations were compared with real X-ray images using standard image quality criteria of MTF, NPS and DQE. Comparison of real and simulated X-ray images shows that this simulation process can be used to display, analyze and compare the output of existing X-ray imaging systems. The results of this study also showed that the model used in this study can be used to simulate a wide range of slit scanning X-ray imaging systems and improve and modify the quality of their images.