This study was conducted to investigate the effective organization of communicative activities in the periods of teaching English grammar skill. The site of this study was High school Teacher Practice-Can Tho University, in the Mekong Delta, Vietnam. The questionnaire and semi-structured interview protocol were the two main tools in gathering data from students and teachers of English at a high school. First, the research analyzed the problems of organizing “communicative activities” in teaching English grammar in high school. The problems related to teachers’ communicative method preference, the deep knowledge of communicative activities, and methodology compromise between teachers and students. They also were the noise and disorder acceptance, readiness for hard work, and the deep knowledge of English and wide understanding life. Moreover, role play is the challenge for weak students and the requirement for them. The troubles concerning with a structure were the most difficulties for students. On the other hand, this study found that noise, disorder, grouping were some suggestions for more effective communicative activities. Besides, furniture and seating arrangement, choice of genres and topics of game, monitoring and time limitation also were the best solutions for better communicative activities in teaching grammar.