Mathematics Instruction is the important section from education according to entirely, because with instruction child's mathematics be trained to thought criticaly, creative, accurate and careful also to act logically. Based on observations in fifth grade of elementary Kedurus I/ 428 Surabaya, it was found problems in learning Mathematics, it was the low student skills in to determine tube volume. this Matter happen because teacher doesn't apply it the correct method in studying determine it volume of tube. don't use it the method that inovatif and correct to studying process to determine it tube volume to caused studying process to direct optimal less and study student in to determine it tube volume also low. this Matter is be proofed with the observation result that to show 50% student yet to reach KKM. Because of, this research to uncrease to determine tube volume skills in fifth grade of elementary school Kedurus I/ 428 Surabaya. The design of studyi is a Class Action Research (PTK). It is performed in two cycles each cycle through the four stages. The data collection techniques that is used by performing the observation, tests and field notes. The use analyzed is qualitatively. The result showed that using the cooperative studying method STAD's type can to level it result study student in to determine it tube volume. To II, persentase activity of teacher to level many 50%. To cycle second happen activity leveling and be told finish, that is 85,7%. Mean while, student learning outcomes as much as 81,3% (26 student) in the second cycle students have finished studying.