A method and a device for arithmetic code package outputting. The method comprises: acquiring the 7-bit output string of the upper bits according to the CodLow value, i.e., the starting position of the probability space to be updated, and using the 7-bit ID string to identify the output characters with undetermined state in the 7-bit output string; acquiring the number of valid bits according to the CodRange value, i.e., the length of the probability space to be updated, wherein the number of valid bits indicates the number of valid bits of output characters in the 7-bit output string according to the CodLow value to be updated; extracting the valid output characters in the 7-bit output string according to the number of valid bits, identifying the output characters with undetermined state among the extracted valid output characters according to the 7-bit ID string; and processing the extracted valid output characters, acquiring and outputting the coding output bytes.