A new method for generation of two dimensional bar code is proposed. Compared with traditional bar code, the new kind of bar code is produced by holography. It not only minimizes complexity of encoding, but also improves ability of volume of information and error correction in bar code by taking advantage of the inherent characteristics of hologram. In addition, by the half-tone technique, it minimizes losing of information of printing process. The simulation and experiment results prove the validity of the method.