The present study aims to analyze the questionnaire item of International Linguistics Olympiad (ILO) with quantitative methods and offer well-wrought considerations for the design of Grammar inquiry task. To achieve the goal, the study devised the criteria of dimensions to analyze the whole question items? "item outline" dimension, "major" item dimension, and "minor" item dimension, then conducted statistical analysis. The results of the "major" dimension offer the followings three findings: first, the questions mainly deal with various types of language such as symbolic languages and minority languages; second, the questions select cultural values of the languages as important inquiry contents; third, to induce and guide inquiry subject`s scientific reasoning, the structures of the questions are mainly shaped in hierarchical types. The "minor" dimension brings two meaningful findings: first, comparison or contrast of the features of more than two languages is the core inquiry activity of the questions; seco and, words are most frequently asked at the "language level" items, decoding at "comprehension level" items, and interpretation at "inquiry level" items. Based on these findings, the study draws two key standards that should be considered in designing grammar inquiry tasks: three central axis of "inquiry subject", "inquiry object", and "inquiry method" and content structures of "material", "means", and "expression." Grammar inquiry task should be designed to pick out a systematic linguistic attribute as an "inquiry object", apply "inquiry method" to lead and guide scientific grammatical thinking, and facilitate high level of thinking for the "inquiry subject." And, to clarify the above suggestions, the study fabricates the item content structure of the grammar inquiry task deign in the stages of "material", "means", and "expression." The study bears its limitation of having analyzed the grammar inquiry task of ILO only. And, to fully utilize the results of the study, more following discussions and experiments that engage the findings of the study to the present Korean language environments are necessary.