Cognitive linguistics provides a new framework of understanding and analysis of basic meanings and semantics of some verbal phrases in English.For many English learners and research enthusiasts,it offers a brand new way of semantic thinking.On the basis of cognitive linguistic theories,this thesis analyzes the semantic meanings of phrasal verbs with the particle back,and discovers that the semantic features of the particle back affect the phrasal meanings.The conceptual meanings of the particle back affect the corresponding verbs on two tendencies:backwardness tendency and return tendency.In addition data analysis reveals that most of the phrasal verbs with back are affected by these two tendencies.