A method for processing a medical image is provided. The method may include obtaining the medical image, and processing the medical image using a processing program. The processing program may include one or more optimized computation units. The one or more optimized computation units may be optimized by an instruction set supported by the at least one CPU. The instruction set may be configured to optimize at least one of an operation time of the processing program, a resource of the at least one CPU occupied by the processing program, and a count of instructions included in the processing program.