Ambiguity is an important and universal linguistic phenomenon in English. This paper mainly illustrates the phenomenon of ambiguity in English by introducing its main two classifications: semantic ambiguity and syntactic ambiguity from semantic perspective, and respectively analyzes the sources that contribute to them through specific examples. Besides, it also illustrates the positive effects of ambiguity in the application of language and gives some advice on the dark side to eliminate ambiguity. Hopefully by such an analysis, it will not only help English learners improve language comprehension and the ability to communicate, but also be of great significance to overcome obstacles caused by ambiguity in communication and master English. This paper mainly illustrates the phenomenon of ambiguity in English by introducing its main two classifications: semantic ambiguity and syntactic ambiguity from semantic perspective, and sponsact ambiguity from semantic perspective, and sponsact ambiguity from semantic perspective, and sponsaly ambiguity from semantic perspective Besides, it also illustrates the positive effects of ambiguity in the application of language and gives some advice on the dark side to eliminate ambiguity. Hopefully by such an analysis, it will not only help English learners improve language comprehension and the ability to communicate, but also be of great significance to overcome obstacles caused caused by ambiguity in communication and master English.