The study was carried out on 299 couples of reproductive age in some mountainous province of Thai Nguyen. Research Methodology: Building a theoretical model after research results are described and analyzed the factors related to the rate of a third child or more high in Vo Nhai district, Thai Nguyen. Results: Proposal for a number of solutions and modeling to enhance the performance of communication family planning program in Vo Nhai. Solution 1: Strengthen leadership, organization and management of communication activities family planning program. Solution 2: To enhance professional training for staff working population. Solution 3: Promote education and communication behavior change on population and family planning. Solution 4: Mobilize community involvement in reproductive health, population - family planning is based on a number of aspects of socio-cultural characteristics of each ethnic group.