The purposes of this research were to study the achievement in Thai language and culture subject of students which was taught by learning center technique and conventional technique in three aspects  1) To create the supplementary learning package in Thai language and culture for Mathayomsuksa 1 and the efficiency of the supplementary learning package was 80/80.   2) To compare the learning achievement in Thai language and culture subject between before and after teaching with learning center technique and  3) To compare the learning achievement in Thai language and culture subject between teaching with learning center technique and conventional technique The sample were 50 Mathayomsuksa 1 students in the second semester of the 2010 academic year, Bangkok Christian International School. They were divided into two equal groups, the control group and the experiment group. The research instruments were the achievement test on Thai language and culture subject. The statistics used in data analysis were mean, standard deviation, and t  test. The results were as follows : showed that  1) The efficiency of the supplementary learning package was 86.10/85.80.  2) The students achievement in Thai language and culture subject of the experiment group after teaching with learning center technique was higher than before with the statistical significance level at .05.        3) The students achievement in Thai language and culture of the experiment group with learning center technique was higher than the normal teaching method with the statistical significance level at .05.