A review on nowadays digital data storage in DNA, most of current digital data are mainly stored on magnetic and optical media. At the explosive era of digital data, the digital data are generated every day and increased at an exponential rate. These traditional media cannot meet the urgent requirement of big digital data storage. With such advantages as high density, high replication efficiency, long-term durability and long-term stability, deoxyribonucleic acid (DNA) is expected as a novel and potential data storage medium. For the new DNA data storage, the files or any data readable will be converted to binary and then encoded to DNA sequences consisting of Adenine (A), Cytosine (C), Guanine (G), and Thymine (T). The data-carrying DNA sequences will be synthesized and stored until data retrieval one day. Once data retrieval, the unique data-carrying DNA fragments will be amplified, sequenced and analyzed. The DNA-based data information will then be decoded into binary and eventually converted to the information readable. Currently, the application of DNA data storage is limited due to such disadvantages as high cost, time-consuming, lack of random-access ability. We still need to face serial tough challenges. However, the seen advances in DNA sequencing technology positively shine the future of DNA digital data storage. DNA is considered as a better storage system is that 215 petabytes (215 million gigabytes) can be stored in just 1 gram of DNA.