There are two principal views in the interpretations of Sengzhao (僧肇 384 or 374-414): one is that he correctly understood the thought of prajña in India; the other is that his thought was one of the logic of tiyong (体用) in China. But they fail to grasp his meaning, so that it is difficult for us to interpret his wu bugian lun (物不遷論). This paper aims to re-examine the system of his thought in his two works and to advance a new interpretation of the Wu bugian lun by positioning it in this system. In the Boruo wuzhi lun (般若無知論) he regarded the state of boruo (般若 prajña ) as two-aspects of one body; that is, the state of ji (寂)―there is no conceptional knowing―and that of yong (用)―everything is known by intuitional knowing―. In the bu zhengong lun (不真空論), in my opinion, things caught by ji were called ‘not being (非有)’ and those by yong were called ‘not nothing (非無).’ Thus he took the true meaning of gong (空 sunya ) as that things are both ‘not being’ and ‘not nothing.’ In the Wu buqian lun he argued that things do not shift through time as real conditions of things known by intuitional knowing.