The purpose of this study is to investigate the Effect of intervention based on Stage of Change Model on the promotion of physical activity of Health Volunteer in Rasht. This study is a randomized controlled trial. The sample size included 160 health active volunteers in health centers in Rasht. Urban health centers will allocate randomly into the intervention and control groups. Inclusion criteria: Willingness to cooperate; the lack of obvious physical problems to do physical activity. Exclusion criteria: Not wanting to continue to work for any reason; illness or accident occurring during the study; The absence of more than one training session; and the absence of pre-test or post-test session. In winter of 2014, Interventional group (80 health volunteers) will receive the intervention based on Stage of Change Model, including: 40 training sessions will be held (each session 45 to 60 minutes lasts, for 8 subgroups, each group: 11 to 14 participants) by lectures, individual counseling, group discussions, role playing, rewarding and texting and also by applying posters, pamphlets, flyers, educational videos and PowerPoint slides. The control group will not receive any intervention by the researcher. Evaluations will conducted by Stage of Change in physical activity behavior, before intervention and after 3 months. After the intervention, we expect significant progress in Stage of changes in physical activity and daily physical activity in the intervention group.