There are five chapters in this thesis. It mainly discusses the effects of Multimedia Instruction Environment (MIE) to the students’ cognitive load and learning performance. Chapter one introduces the research background and design principle which is based on the project “A study on experiment-based dynamic mathematics teaching”. Chapter two explores and reviews the Cognitive Load Theory (CLT) and Multimedia Learning Theory (MLT). Both theories are discussed in order to find out the related theory foundation. Chapter three presents the research methods and procedures. Quasi-experimental is the main method in this study. Chapter four analyzes the experiment data and discusses the results. There are three kinds of experiment results analyzed in this chapter, including students’ cognitive load measurement, students’ learning performance, and their relationship. The conclusions and suggestions are proposed in Chapter five. The conclusions of the thesis are summarized in the following. 1. MIE could not improve the students’ post-test performance. The reason might be caused by the simple learning materials and some CL effects during the teaching process, including split-attention effect and redundancy effect. 2. MIE could not reduce the students’ post-test CL. The reason might be caused by the redundancy effect in worked example designs, and split-attention effect and redundancy effect in teaching process. 3. There are no difference between male and female students in post-test performance in MIE. 4. There are no difference between male and female students in post-test CL in MIE. 5. There are no difference between male and female students in CL in MIE during the whole learning process. 6. MIE could not improve students’ learning tasks performance. The reason might be caused by the too simple task question designs. 7. MIE could improve the students’ homework performance. 8. MIE could not reduce students’ learning CL. Keywords：Cognitive Load, Multimedia Instruction Environment, Learning performance