A color bar code comprising a first code block. The first code block comprises: a header region, comprising at least one header color bar, wherein the header color bar includes a predetermined asymmetric optical feature; and a code region, comprising at least one code color bar. The color kind or a color sequence of the code color bar indicates a code. Such color bar code can comprise more information and the contained therein is more easily to be acquired. A corresponding code determining method and a corresponding code determining system are also disclosed.