The purpose of this research were to create and determine the efficiency of computer assisted instruction lesson on electronic circuit multimedia for secondary school students (grade 9) Triamudomsuksanomklaononthaburi school. The research sample consisted of 120 students of secondary school students (grade 9) during semester 2 in the academic year of 2012. The data were analyzed using mean standard deviation level of difficulty and discrimination power. The results found as follows : The efficiency of computer assisted instruction lesson electronic circuit multimedia for secondary school students (grade 9) is 80.15/83.35 and the students’ satisfaction with the computer assisted instruction lesson electronic circuit multimedia was at highest level ( = 4.60 S.D = 0.74)