A computerized attention-training game system has been developed to support attention training for school-aged children. The present system offers various types of computer games that provide training in different aspects of attention, such as selective attention, sustained attention, and divided attention. The N-tier architecture of the Web-based applications was applied for the development of this system. Children can access the system to play interactive games in a Web-based environment by using smart phones, tablet computers, or personal computers. A complete set of training information is collected in which the system provides a training portfolio mechanism to record the training progress and performance of the player. Children may benefit with the challenging features of attention demands during game-playing and the observer may gain detailed information of the training process. The game scenario helps motivate children to practice attention tasks with interactive play and immediate feedback.