The purpose of this study is to analyze the influence of learning strategy, learning motivation, family strength, social support and the subfactors of the variables on the academic achievement of vocational highschool students by the level of achievement. The subjects for this study were 196 students of vocational high school in the second semester of 2016 and all data collected were analyzed. The school is located in a small city and is considered to be a middle level of distinction among vocational high schools. The results of analysis were as follows. First, learning strategy and learning motivation differ in the order of the achievement of academic achievement, high-level, middle-level and low-level. Family health and social support differ in terms of academic achievement, high and middle-level, and low-level. Secondly, learning strategy, learning motivation, family health, and social support in academic achievement have significant implications for achievement, but peer support is minimal. Among the subfators of the variables, there is a positive effect on the cognitive strategy(R=.48), all of the subcomponents of the learning motivation(R=.52), ability to perform problem solving(R=.21), parental support(R=.33), but family communication, sharing the value system, and peer support showed no positive influence. The results of this study differ in the influence of each variable on the academic achievement level of the vocational high school students academic achievement level. Therefore, it is suggested that academic achievement variables should be selected and approached by the achievement level.