Augmented reality (AR) technology is mainly composed of feature extraction, feature points matching and 3D object drawing to impose virtual information onto the real camera. Hand tracking method is designed to realize interactive AR system to further enhance user experience (UX). However, feature extraction, feature points matching, and hand tracking all require high computational cost. To achieve real-time implementation on mobile, we proposed a Mobile Augmented ReAlity Interactive System based on cloud computing (MARAIS). Cloud side is responsible for heavy tasks that need sufficient computational capabilities, and device side performs sensing, detecting and displaying. Device/cloud architecture has been designed to maintain tolerable processing delay with minimum communication overhead. To validate the suitability for real-time interaction, MARAIS is combined with a picture book to realize a digital learning system. Implementation of interactive AR system based on cloud computing eases the requirement of data storage, memory, and computational power at device side.