This paper is a summary study of team Postgraduate on 11th grade. The objective of this study is to develop a learning model based on problem solving which can construct high-order thinking on the learning mathematics in SMA/MA. The subject of dissemination consists of Students of 11th grade in SMA/MA in 3 kabupaten/kota in North Sumatera, namely: SMA Swasta Yapim Taruna Stabat Kabupaten Langkat, SMK Negeri 6 Medan, SMA YPK Medan, and MAN Lubuk Pakam Kabupaten Deli Serdang. Instrument of collecting data used are questionnaires, observation guidelines, interview guides, students' mathematics textbooks for 11th grade in SMA/MA, Teacher's guide book, instrument of pre-test and post-test. Development of model are adopted from Thiagarajan's model and Semmel & Semmel's model. This research has compiled teaching materials in the form of textbooks for 11th grade in SMA/MA and teacher's guide book that includes the structured steps of solving mathematical problems based on problem solving which can construct high-order thinking. Results of dissemination showed a significant improvement of students' problem solving ability at four schools in three kabupaten/kota in North Sumatera.