This study aims to investigate the influence of Multimedia Computer-Assisted Instruction on the achievement and the geography learning manner of the chapter “map”. The instruments of this study are consisted of “Geography Learning Attitude Scale”, “Geography Learning Ability Scale”, “The Pretest and Posttest concerning the understanding of the chapter „map‟ and also students‟ learning manner”. It adopts the pretest-posttest equivalent groups design. The subjects of this study were 98 Junior 1 students who studied at the Workers‟ Children High School. The 47 students in junior 1B class were selected as experimental group. The 49 students in junior 1A class were selected as controlled group. After processing and analyzing the data consisted of Average, Std. Deviation, Analysis of Covariance and T-test, four significant findings are reported: 1. Significant progress is reported among students with different academic achievement in the experimental group. And the progress range is from the high-level to the low-level students. 2. No significant difference is found among students with various learning manners in the experimental group but all of the students had progress in the achievement of the chapter “map”. 3. The experimental group‟s achievement of the chapter “map” is more outstanding than the controlled group but no significant difference is found. 4. The experimental group had positive increase in geography learning manner of the chapter “map” while the controlled group had negative increase in such manner. And no significant difference is found.