. The purposes of this study is to improve performance maths lecturer to the processof them through the lesson study in the implementation of learning. It used research action. Itis to apply lesson study to improve their performance maths lecturer . Data collection methodby observation of lecturers model at the lesson, questionnaires and in-depth interview. Thisstudy was located at High School Management and Computer Science in Surakarta. It wasstart from Oktober – November 2016 by two cycle research. Subject at this study are 4 lecturerexpertise on mathematics. Instrument of this study are observation sheet, interview guidelinesand close questionnaires about students response after lecturers teaching. The method ofanalysis data using approach cyclic process is analyzed data since the act of learningimplemented ( from plan-do-see ), developed during learning lasted until obtained learning /professional quality. Data analysis methods it consists of three ways namely; reduction of data,presentation of data and verification, inference. The result showed that the implementation ofthe lesson study can improve performance maths lecturer at learning process.