The phytophagous insect, Epiblema strenuana, is an effective biocontrol agent against Am-brosia and Parthenium, and was introduced to China in 1990 to control Ambrosia artemisiifolia. After asmall scale release in Hunan Province, E. strenuana established and begun to spread. Host specificity andfeeding studies in Hunan have indicated that there are four host plants in China, A. artemisiifolia, A. trifi-da, Xanthium sibiricum and Parthenium hysterophorus. These plants are all weeds that need to be con-trolled. However, there are still some different views among scientists about the merits of this release becauseof potential effects on non-target species such as Helianthus annuus, and uncertainty about climatic suitabili-ty. To address these concerns, the CLIMEX system was used to predict the possibility of establishment of E.strenuana with A. artemisii f olia , A. tri fida , and P. hysterophorus at 85 meteorological locations. Also,the probability of E. strenuana co-establishing with A. artemisiifolia, A. trifida or P. hysterophorus wasevaluated quantitatively by bioclimatic risk index (BCRI) transferred from ecoclimate index (EI). Moreover,the hypothetical adaptation of E. strenuana to H. annuus as a host, were evaluated by bioclimate matching.These results help to predict the potential spread of A. artemisiifolia, A. trifida, P. hysterophorus and e-valuate the merits of further releases of E. strenuana in China.