There are three purposes of this research. First, to know how the School-Based Quality Improvement Management (MPMBS) was being implemented in 1st Senior High School of Sukoharjo (SMAN 1 Sukoharjo). Second, to understand what the supporting and contrary factors of the MPMBS implementation were. Third, to know the actions taken by the School to maximize the supporting factors and to avoid or delete the contrary ones. This is a qualitative research with qualitative discription method. The subject of this research was SMAN 1 Sukoharjo. The data sources which were used in this research are informan, place or location, documentations, and archieves. Informations are gathered by interview, observation and documentation. This study employed triangulation validity test while, interactive analysis was used to do an analytical test. The results showed that some criterias, which are curriculum management, student management, infrastructure, public relations, financing and the process of teaching and learning, in MPMBS were already applied by school. As general, the implementaton of MPMBS in SMAN 1 Sukoharjo was good.