Abstract: Hyphantria cunea Drury not only damages natural resources,but also limits the multi-functions of host-plants.In addition,it causes the great loss of human eyesights,psychology and everyday life,etc.Past studies recognized its damage only through the changes of materials such as forest resources,ignoring its social and economic nature.And at present,the researches on its loss evaluation are not adequate,especially lacking of quantitative analysis,and the common concern from the whole society is not brought forward.Therefore,it is in great need to analyze and evaluate the damage and loss systematically and scientifically caused by H.cunea.In accordance with scientific,systematic and comparable principles,combining its own characteristics,the paper firstly identified the sorts of damage and loss caused by this invasive species.Then the index system of its loss evaluation was set up,up to 47 indices,including two first-level indices,nine second-level ones and 27 third-level ones,and the connotation of main indices was elaborated for the first time.Based on the indices,the study also established the measuring methods.