A holographic data storing method includes the steps of: encoding original data to generate holographic data according to a codeword to symbol relation; and recording a hologram corresponding to the holographic data onto a holographic storage medium. In the codeword to symbol relation, a plurality of sample symbols corresponds to a plurality of codewords. Each of the sample symbols corresponds to a pattern having N*N pixels. There are M bright pixels in the N*N pixels, wherein N and M are positive integers and M is smaller than N*N. A hamming distance of the sample symbols is greater than or equal to 4, and a two-dimensional run-length of the sample symbols is greater than or equal to 2.