From the right-to-know perspective, the paper compares the Chinese and Japanese government information disclosure system under the background of big data. It concludes that the Chinese government should learn from the Japanese model that the government information disclosure system should be legalized based on the right-to-know principle. It claims that the scope of subjects should be enlarged under the protection of their right of claim for government information disclosure, with the improvement on data management and restriction rules on right-to-know. Therefore, the traditional management of government information disclosure system in a closed administrative way can be gradually reformed to an open information-oriented one, aiming at protecting right-to-know to keep up with the era of big data.