The purpose of this paper is to examine the ontological position of Huiying, a Buddhist commentator of the Northern Zhou dynasty (557-581), in his Dazhi du lun shu. This text is the only extant Chinese Buddhist commentary on the Dazhi du lun大智度論(Skt. Mahāprajñāpāramitopadeśa) and was a text preserved by the Northern Masters of the Four Treatises School四論師in the Southern and Northern dynasties; as a consequence, it has considerable research value for our understanding of Chinese Buddhism during this period. This paper argues that the ontological position of Huiying can be understood on two levels. First, he takes dependent origination and non-intrinsic-nature from the structures of conventional truth to illustrate that facts of existence are analogous to the assertions of anti-realism. However, though his position denies the substantiality of existence, it nevertheless acknowledges the temporality of existence in the context of dependent origination and unity, a point which differs from anti-realism. Second, within the structures of ultimate truth, Huiying assigns an ontological commitment to true original nature, bringing his position into alignment with Plato's realism, but in Huiying's explanation, existence is not derived from the ideal forms. Furthermore, by reconstructing Buddhist thought in the Southern and Northern dynasties in which Huiying was situated, we discover that he was influenced by Daoan道安and interpreted the concepts of reality (shixiang實相) and wisdom (bore般若, Skt. Prajñā) in the Da zhidu lun through his understanding of the Nirvana School's涅槃師concept of the eternality of Buddha Nature and the Dilun School's地論師concept of original purity of the store consciousness (aliyeshi阿梨耶識, Skt. ālayavijñāna). This ontological disposition of Huiying's interpretation is the result of fusing together the thought of different Northern Buddhist schools and their texts from the Southern and Northern dynasties periods. Nonetheless, this also suggests that the ontological position of Huiying is perhaps not the product of absolute influence from the thought of different Buddhist schools at that time. Instead, it was the result of an interpreter mixing together concepts from different scriptural and commentarial systems, which resulted in alterations to Huiying's interpretations of Madhyamaka philosophy.