Mahā-prajñāpāramitā Sūtra, Mahā-prajñā Sūtra in short, contains sixteen assemblies, six hundred volumes, whose Second Assembly, Middle Class, are composed of 78 volumes, not so much as The First Assembly. However, only vájra-cchedikā-prajñā-pāramitā-sūtra, The Ninth Assembly, has been passing on as one of the most popular Buddhist scriptures nowadays. It seems that what took Monk Xuanzang(玄奘) his lifetime efforts is now only for academic uses, which is a huge pity. Accordingly, this article is meant to aim The Second Assembly, unveil more and further prajñā by combing simple interpretations of scriptures in modern works. While collecting, surveying and studying related materials, I was enlightened by three Buddhist works in modern times. First, in YueTsangZhiJing , a catalogue of scriptures and introductory reading, edited by Quyi Zhixu of Ming Dynasty, 8 volumes of Mahā-prajñā Sūtra ZhiJing corresponds to modern people's fast-paced minds with its simplified, organized summaries. And in "Buddhist Analects of Ouyang Jingwu" by Ouyang Jingwu, a renowned lay Buddhist in Qing Dynasty and exponent of Yogacara, three volumes of Narration of Mahā-prajñāpāramitā Sūtra are engaged in explicating The Second Assembly briefly, explicitly and accurately. Last, Abhisamaya-alaṅkāra by Maitreya is oriented to assist people in studying Mahā-prajñā Sūtra. Though not incorporated in Northern Buddhist Tripitaka, this work is placed much value in both India and Tibet. Modern Buddhist scholars didn't stop annotating it, such as the Venerable Fatsun of Qing Dynasty, who wrote Brief Explanation of Abhisamaya-alaṅkāra. Thus, this article will target "On Joy" of The Second Assembly of Mahā-prajñā Sūtra, and compares the number of words, frameworks, methods of interpretation in the three modern Buddhist works mentioned above, not merely to figure out the essence of Mahā-prajñā Sūtra but to cater to the general public, who like to grasp meaning in outline. Serving as good and convenient tools, those interpretation methods will hopefully popularize Mahā-prajñā Sūtra gradually.