This development aims to develop learning implementation plan, and develop evaluation of lesson planning to write text of observation report with model of project-based learning of class X SMA Negeri 1 Sendawar. The development method used is Research and Development (R & D) with Borg & Gall development model. The study population is all students of class X SMA Negeri 1 Sendawar which amounts to 93 students. Trials are conducted in two stages: test by small groups and large group trials or field trials. Observation data collection techniques, interviews, and tests. Data were analyzed using descriptive and descriptive quantitative statistics. Development of the implementation of learning to write text reports of observation results of project-based learning model on high school students X high school has a very good response. This result is obtained from the assessment instrument of students as much as 60 students and shows the percentage value of 92.57% fall into very good category. Product development of learning planning writing text observation report with project-based learning model has a very good quality shown by the excellent design validator validation of 97% and excellent material validator assessment of 95%. Product development of learning planning to write text of observation result with model of project-based learning is effective in improving student learning outcomes as evidenced by the average increase of student learning outcomes in small groups of 67.16% value increased to 87.16%.