The study aims at constructing a customized portal system that can help students to build their learning knowledge. It also investigates students' learning effects on learning behavior, network use condition and learning outcomes for the use of the system. The sample comprised 60 12-year-old elementary school Year 5 pupils in Yunlin County. Qualitative and quantitative approaches were taken in this research. The data were collected from questionnaire and observation. The results show that the system can definitely help students to perform knowledge building for learning activity. The system is actually helpful for network learning.