The aim of the research is reveal “The Effectiveness of Curriculum Developer in Science in View of Project Based Learning to Developing Problem Solving Skills for Primary Stage Pupils",the research used the experiment desien based on one group with measurement (before – after), and the research group consisted of (46) pupils in the grade four of primary stage, the development of curriculum in science in view of project- based learning, problem solving skills test in science, and the research tool was applied before and after on the research group, then satistically processing data.
The results of the research concluded that there is a stastiscally significant difference at the level of significally (0.01) between the average scores of the research group in the two application, pre and post, to test the problem solving skills in favor of the post application, the result showed the effectiveness of one unit of curriculum developer in science to developing problem solving skills of the pupils of the research group.the research recommended the need to reconsider the science curricula at the primary stage: to built it in view of project-based learning; because of the role to help realize the importance of problem solving skills in science.