The invention relates to an arithmetic decoder based on context self-adaptive binary, wherein said decoder comprises an arithmetic decoder controller, a data interface, a mark subscript, a context subscript increment counter, a context manager, a decode engine and a mark detector; the controller is used to command external modules, the communication between nearby information and grammar element value, to simplify the interfaces of whole decoder; the data interface is used to communicate code flow with outer space, to reduce the communication times between decoder and external code flow; the mark subscript and the context subscript increment counter can quickly calculate out the mark subscript and context subscript increment; and the decode engine can realize the decode at several modes, to save the hardware consumption and accelerate the decode.