Learning is currently using the scientific approach, through direct interaction with learning sources. The educators or teachers at the school are expected to use appropriate learning resources. Local potentials that are spread around in the form of learning resources should be of concern to organized, so empowering positive for all student’s learning. Not much research to develop teaching materials based on local potential, example river potential. One of river of Tanah Laut where phytoplanktons are living is Panjaratan River, not many people know that phytoplanktons can be used as teaching materials, specially protists. This research aimed to describe the validity of developed teaching materials. Research method used in this research was Research and Development. Developed teaching materials were validated by experts as well as the partner teachers and tested by students before they were revised consequently. The experts were 3 lecturers of Lambung Mangkurat University and students mentioned were from SMAN 1 Pelaihari. The results showed teaching materials were quite valid according to the expert (80,8%) and partner teachers (78,9%). Finally, the materials can be used.