This research is motivated by the problem of the low ability of students in understanding the concepts on science learning. It is because the application of learning is classical, and lack of use the props in the learning process. Based on these problems, researchers apply the model of Brain Based Learning as an effort to improve the student's understanding. This research aims to know (1) the description of science learning process about the concept of water cycle by applying the Brain Based Learning models in fifth grade of elementary school, (2) the result of the student's understanding in fifth grade of elementary school on water cycle concept by applying Brain Based Learning models. This research involved 40 people of fifth grade students at SDN Sukahaji 01 as subject of research. The research method used is classroom action research with Elliot model design, which consists of 3 cycles. Data were obtained from teacher's and student's observation sheets, field notes, student's understanding evaluation sheet, and documentation. The data's analysis technique used is qualitative and quantitative. Based on the results of this research, it is known that (1) The process of science learning about water cycle concept by applying the Brain Based Learning models consists of seven stages: pre-exposure, preparation, initiation and acquisition, elaboration, incubation and memory encoding, verification and confidence checking, celebration and integration, (2) Student's understanding on learning water cycle concept by applying Brain Based Learning models has improved. This is evidenced by the increase in the average value of student's understanding of evaluation is the first cycle of 68,22, the second cycle to 74,53, and the third cycle to 81,51. Based on the results, Brain Based Learning model can be used as an effort to improve student's understanding in science learning in elementary school.