This study focuses on analyzing the existing risk assessment protocols on alien (exotic or non-native) species in somes of European countries, USA - Canada - Mexico, and Australia - NewZealand. Experiences from these countries will be summarized in this paper, including scope and completeness of each protocol, data requirements, scoring method, uncertainty, user-friendliness, and criteria and catergories for impact assessment. These criteria play a key role to help imply the feasibility of a protocol on risk assessment of alien species, and are also the basis for making recommendations to apply it in Vietnam.