The aim of this paper is an elucidation of the Mahāsāṃghika doctrines in the Apidamo da piposha lun 阿毘達磨大毘婆沙論 and the Apitan piposha lun 阿毘曇毘婆沙論. A previous work by Watanabe Baiyū collected all the doctrines which had been argued by many types of schools in two Chinese translations of the Mahāvibhāṣā. However, in his work, almost all the doctrines were not satisfyingly examined. In this paper, when I examined the Mahāsāṃghika’s doctrines in the Apidamo da piposha lun and the Apitan piposha lun, I compared those doctrines with the Samayabhedoparacanacakra in order to comprehend the character of the Mahāsāṃghika. As a result, two points were revealed. One is the accuracy of Watanabe’s collection. The other is the necessity to reconsider some Mahāsāṃghika doctrines. Especially relating with latter point, the evidence for the prejudice that the Mahāsāṃghika is more progressive than the Sarvāstivāda is not supported by this research.