This research was aimed at: 1) studying students’ learning achievement using the project-based integrated learning process on “Ngoen-thong-khong-mee-kha” or “the Value of Money” with a target of 80% of the students achieving over 70%; 2) developing a project-based group process of 41 Prathom Suksa 2 students from Demonstration School of Khon Kaen University, Primary section (Modindang) in the second semester of 2012. The variables included: 1) achievement of Grade 2 students after the project-based teaching and learning process and 2) the project-based group working process. The research tools used were: 1) integrated teaching plans constructed by the teachers for mathematics, Thai, social sciences, and art work subjects under the topic, “Ngoen-thong-khong-mee-kha” or “the value of money” and 2) the students’ behavior record form. The method applied was classroom action research (CAR) comprising 1) stimulation, 2) planning, and 3) presentation. Quantitative data was collected and computed in percentages, means, and standard deviations. Qualitative data was obtained from observation of students’ behavior in group working, their work outcomes during and after research implementation, and from observation, interviewing and evaluation of work outcomes.