After 3-year's study, we have developed a standardized Chinese Language Proficiency Test for learners whose Chinese is his/her second language. In order to define the level of proficiency, we have conducted basic research in the area of vocabulary, grammar and culture for one year. Several small scale of research was also carried out to decide the format of a language test. Then, expert Chinese language teachers were invited to write test items according to the test framework. Draft items were then reviewed by another group of experts. A pilot study was conducted to select and revise test items based on the psychometric properties of items. There are 2 levels of test books: general and advanced levels. Each level has a parallel test. In 1997, 939 Chinese language students were recruited to take the tests. We have also had Taiwanese elementary, junior and senior students to take the same tests. The purpose was to validate the relationship between the level of difficulities and the experience of learning. All the results show that the Chinese Language Proficiency Test is a valid and reliable test. It can discriminate students with different learning experience and learning time. We recommend the test to the Mandarin language centers for the purpose of replacement or fro the evaluation of students' Chinese language abilities.