The purpose of this study was to analyses the learning environment and goal orientation on students' physical activity time, knowledge, and enjoyment in fitness education units of physical education in high school. Twelve grade high school students (n= 176) and their physical education teachers from two separate schools participated in this study. One teacher and school was involved as a treatment group and the other was used as a comparable group. The treatment group received a program of teaching strategies for positive discipline with Fitness Education Curriculum (FEC) while the comparable group did not. The students in the both groups were asked to complete the Perception of Physical Education Learning Environment Scale (PELES), Goal Orientation in Sport Questionnaire (GOSQ), Student's Enjoyment to Physical Activity questionnaire (CAPA), and Health-related Fitness Cognitive Test (HFCT) before and after the interventions. Information was collected during the first two weeks for the both groups without any interventions. From 3rd to 6th week, the PE instructor in the treatment group, only, received the teacher education program. From the 7th week to the 14th week, the PE instructor in the treatment group was required to use teaching strategies for positive discipline with FEC teach the fitness lessons and. From the regression model, the factors of task orientation and perceived challenge learning environment in PE could be effectively predicted student's enjoyment to physical activity in the FEC of PE classes (b=0.39 & 35; t=5.39 & 4.93, p< .001). The findings also indicated that students perceiving a higher challenge in the PE learning environment could be a positive factor to influence the fitness knowledge test in PE classes (b=0.15; t=2.00, p< .05). For the Students' learning outcomes, fitness knowledge and enjoyment for the treatment group not only had more significant improvement than the comparable group in the post-test (t=8.80, p< .0001), but also had a significant increase after the intervention (t=3.25, p< .01). However, there was no significant different between the two groups in the pre-test. Finally, positive discipline in physical education classes recognizes the importance of the classroom environment on the student learning and behavior. Positive discipline works to create an inclusive and challenge learning environment where students want to practice, where they keep practicing hard and trying hard, and where they feel PE classes challenge my ability. From a motivational standpoint, it appears that students who perceived this type of learning environment and took advantage of this achievement motivational climate, had much to gain.Keyword(s): high school issues