Subjectivity and subjectification is an important motivation to the formation and development of syntactic structures. This paper,following Traugott’s subjectification theory,establishes a model for the analysis of subjectification of if-conditional constructions called ‘four-dimensional correlated continuum of subjectification’ on the basis of cognitive,psychological and linguistic structures. The ‘continuum’ shows that the subjectification process is a gradient phenomenon,and the ‘four-dimensional’ indicates that subjectification can be operated in logical,semantic,syntactical and pragmatic aspects. The paper is an attempt of application study of the theory of subjectivity and subjectification and it provides a new perspective for the study of development of the English complex structures.