摘要:This research report is an analysis of preposition on, in, at. The writer choosespreposition on, in, at because preposition is one of basic grammar that is usuallyused by people in speaking and writing. The aim of writing this research reportis because the writer wants to know how far the students master and understandpreposition especially preposition on, in, and at. And the writer wants to knowdifficulties for students in mastering preposition on, in, at. The writer usesquestioner in analyzing the mastery of preposition on, in, at for first yearstudents at Gunadarma University. The questioner is in multiple choices whichconsist of 20 questions. The sample is 40 students. The level of understandingfor first year students at Gunadarma University is below average or poor. Mostof the students have difficulties in determining sentences which talk about aninstitution in that street, about a place we think of as a point rather than an area,or something within a larger space. Key Words : Mastery, Preposition on in it, Analysis