The purpose of this study is to find the causes of the physical education (PE) learning under- achievement and to classify the style of the PE learning underachievement by the cause. In the study, 213 students(boy;116 , girl:97) of the sixth grade (students) in the Daegu elementary school are tested by the learning ability of PE and are selected 51 subjects(boy:21, girl: 30) among them. To fine the causes of PE underrachievement, coordination (bar-gripping reaction time, grunk flextion, colsed - eye foot balance), strength , %fat, physical emotion, EQ and IQ are measured and achievement & ramily environment are investigated. And the styles of the PE learning underachievement are classified by the cause. The result of this study are following . A. among the under 5% children of PE learning ability, underachieved children are selected professional discussion. B. according to main cause, PE learning underachievement are classified 8 male styles and 10 female styles. First, 9 male styles are following. Style Ⅰ - Pool Knowledge of PE learning cause, Style Ⅱ - Difficulty of PE learning cause, Style Ⅲ - Emotion cause , Style Ⅳ - Cognition cause , Style Ⅴ - Physical fitness cause, Style Ⅵ - Habbit cause, Style Ⅶ - Psychology cause , Style Ⅷ- Personality cause Second, 13 female style is following. Style Ⅰ-Pool knowledge of PE pearning cause, Style Ⅱ- Difficulty ofPE learning cause Style Ⅲ- Obesity cause , Style Ⅳ- Habbit cause, StyleⅤ-Physical fitness cause , Style Genetic physique cause, Style Ⅶ- Habbit cause , Style Ⅷ- Psychology cause, Style Ⅸ- Personality cause C. The PE learning underachievement is not showed in each PE learning ability , but one ability influenced another.And the cause analysis movement items if able to classified because of organizing the causes. D. In the ratio of the PE learning underachievement, boy students are more than girls. As a result there is sexual difference in the PE learning underachievement . Especially girl students are simply affected by the emotion cause. E. The important simple cause of the PE learning underachievement is obesity ; 1 boy, 2 girls F. In the case of boys, ther are 5 multi-causes,but girls 5 simple -causes. G. 5 boys and 2 girls are classified ectomorphic obesity which is short fo muscular power . This phenomenon is because of muscle decrease by inactivity and %fat increase by overnutrition.