This study aims to explore the current practices of integrating information technology into team-teaching in fourth-grade mathematics class. This study discussed how the proposed teaching method affect students’ learning achievements and attitude, as well as the teachers’ professional growth and difficulties of implementation.. The method of this study is based on action research. The participants of this study are 18 fourth-graders in Hsinchu county. The study is carried out over the period of one semester in which the curriculum is divided into seven research units from September in 2006 to January in 2007. The resulting data for the study are collected from periodic assessments, questionnaire, video-taping of the teachers’ teaching, interview record, students’ feedback and teachers’ reflective journals, etc. The research results are as follow: 1.The study shows that integrating information technology into team-teaching in mathematics curriculum can improve students，achievement because of team-teaching can provide students more learning opportunities and immediate instruction, and the use of teaching software combined with life-related instructions flash made the materials easier for students to understand. 2.The study indicates that the use of Integrating Information Technology into Team-Teaching was helpful in fostering students’ interest in mathematics. Students developed a positive learning attitude toward the subject through the application of information integration technology. The novelty of such method promoted students’ interest in the subject, lessened students’ sense of apprehension, and increased students self-confidence. The lively teaching approach prompted students to participate actively and to express their opinion enthusiastically. The good interaction between teachers and students could awake students’ enthusiasm of studying. 3.The study demonstrates that through constant self-reflection, evaluation, correction, and implementation the team gained professional growth in areas of teaching attitude and the capacity of teaching. Though this action research, the researcher improved not only students’ learning achievements and attitude but also improved researchers’ teaching skill and research ability, had accumulated the experience of integrating information technology into math teaching. According to the results of this research, some suggestions about integrating information technology into team-teaching for mathematics class and further studies are proposed.