This paper used Cognitive Linguistics to study Generalizaton of ‘Ranhou(然後)’ in Modern Chinese. The Cognitive Mechanism on Generalization of ‘Ranhou’ is Metaphor and Subjectivization. The results are as follows: Metaphor affects the Generalization of ‘Ranhou’. The function of Metaphor specifies the meaning of ‘Ranhou’. ‘Ranhou’ can be divided by ‘Ran’ and ‘Hou’. ‘Ranhou’ has ‘after agreement or confirmation of preceded utterance of mine’ and extends to ‘on premise preceded utterance or event’ furthermore, and therefore can have possibility having various functions in Park, Chan Wook(2011). Subjectivization also can affect the Generalization of ‘Ranhou’. ‘Ranhou’ is developing from expressing objective sequence into subjective sequence. From objective scanning to subjective virtual scanning, ‘Ranhou’ forms a Mental Scanning chain; its semantic nature also develops from objectivity into subjectivity. ‘Ranhou’ had developed from expressing conditional relationship to expressing sequential relationship, and was generalized to express logical sequential relationship and non-sequential functions.