The purpose of this study is to develop the standardized instrument for diagnostic assessment of coursework in Korean Language Education. For this purpose, we develop the elements which can show the Korean Language Ability. We presented the elements of the Korean Language Ability that is related the 7th curriculum. The developed instrument was applied as a diagnostic assessment at two elementary schools in seoul. The students who participated in this study were 793 that is consisted in 268 third graders, 264 forth graders, and 261 fifth graders. Difficulty, reliability, discrimination index were analyzed and revised tests items to qualify standardized test. Cut off score was decided for using these test as diagnostic assessment. And that was confirmed two methods cooperatively norm referenced test as well as criterion referenced test. (The National Institute of the Korean Language)