Effects of using the Teaching and Learning Model of Chulalongkorn University Demonstration Elementary School on Mathematics and Thai Learning Achievement of Students in School Network : The theory of perceibutes The purpose of this study was to study the effect of using the Teaching and Learning Model of Chulalongkorn University Demonstration Elementary School on Mathematics and Thai Learning Achievement of Students in School Network. The subject of the study was Sirimongkolsuksa School Nonthaburi, Chulalongkorn University Demonstration Elementary School’s School Network, who use Chulalongkorn University Demonstration Elementary School’s model. The instruments used in this study were the Observation form, Long plan project, Supervision form, Lesson plans, Mathematics learning achievement test, Thai language learning achievement test, Structured interview form and Satisfaction form. Data were analyzed by using t-test independent. The results of this study were as follows : 1. Students in high ability group, moderate ability group, and low ability group had higher mathematics score and higher thai language score after received treatment than those before received treatment at .05 level of significance. 2. Students in high ability group perform no significantly different in both mathematics and thai language. 3. Students moderate ability group and low ability group had higher mathematics score and higher thai language score after received treatment than those before received treatment at .05 level of significance.