The invention discloses an omnidirectional readable two-dimensional bar code system comprising a coding area and synchronization code elements. The coding area is formed by unit nodes arranged in an N*N matrix mode, wherein the N being a positive integer is larger than or equal to 11; and the synchronization code elements are distributed at the periphery of the coding area. Coding information sequences are distributed on all unit nodes arranged in a matrix array mode successively along a preset identifying and reading direction by using specific unit nodes as starting points; the starting points are identified by directional code elements. The directional code elements consist of a starting code element and 27 subsequent code elements; and the 28 code elements are distributed at different specific positions in the coding information sequences. The different specific positions are at four unit nodes at four corners of the matrix array, at two unit nodes adjacent to the unit node at each corner, and four unit nodes of each side center of the matrix array, wherein each two adjacent unit nodes of the four unit nodes form one group and the two groups are distributed at the two sides of the midpoint symmetrically. Therefore, omnidirectional reading can be carried out. In addition, the invention also discloses an identifying and reading method for an omnidirectional readable two-dimensional bar code system.