Objective To present the methods of medical image quality assessment and optimization.Methods Based on human vision characteristics,the image vision quality parameters were analyzed in order to find the objective vision parameters influencing global image quality.An empirical equation to assess a single (no-reference) image quality was belt when these parameters which influence the visual image quality were analyzed and synthesized.And according to the features in medical image quality assessment,the generally single (no-reference) image quality assessment equation was modified to the medical one.Using a transformation formula,a thread of the medical image quality optimization was presented.Results (1) An empirical function,CAF,which is used to assess a single (no-reference) image quality,had been established; (2) The optimal examples (lateral abdomen and longitudinal spine) of MRI images in medicine were shown by a Zadeh-X transformation.Conclusions (1) The visual quality for 3T image is better than 1.5T; (2) 1.5T and 3T images could be optimized,respectively; (3) The resulting image quality,that 1.5T image is optimized,approaches to 3T image quality.Conclusions (1) This methods can be used to improve the image quality imaged by MRI equipments with 1.5T and lower than 1.5T ; (2) This methods can be used to elevate other medical image quality,like as ultrasonic imaging,variant CT image and combined CT images; (3) The automatically adaptive optimization methods for medical images could be studied further.