The purposes of this research were: 1) to compare learning achievements of vocational certificate students before and after receiving direct instruction model supplemented with peer assisted technique, and 2) to compare machine tool practical skills in mild steel turning of vocational certificate students after receiving direct instruction model supplemented with peer assisted technique with the 75% criterion. The sample used in this research is vocational certificate students of Udon Thani Polytechnic College, in the second semester of 2022. the sample consisted of 20 students by cluster random sampling. The research instruments consisted of 1) direct instruction model supplemented with peer assisted techniques lesson plan, 2) an achievement test on introductory machine tool subjects, and 3) mild steel turning practical skill test. The statistics used to analyze the data were mean, standard deviation, percentage, and an independent t-test. The research results were as follows: 1. Vocational certificate students who received direct instruction model supplemented with peer assisted technique had mean scores after learning higher than that the one before. 2. Vocational certificate students who received direct instruction model supplemented with peer assisted technique had skills of machine tools in turning of mild steel mean score after learning which was higher than the set criteria of 75%.