Communication skills is an important element in science lessons to help students interact and find solutions for a problem of scientific. The students need to communicate with other people to collect and disclose information or their ideas orally and writing. Communication skills training to help students directly involved in building their knowledge. The purpose of this research is to know the effectiveness of the cooperative learning type NHT assisted with mini laboratory to train communication skills of junior high students. The data of study were colleted trough writing communication skill test before and after the implementation the learning strategies. Oral communication skills test is done by observation during the learning activities. The results of this research shows that there is increased communication skills students between before and after the learning is applied. This shows that the cooperative learning type NHT assisted with mini laboratory effective to train the communication skills of  junior high students.