With the development of the hardware and software platforms, we can implement the deep learning model on the mobile device for mobile augmented reality (AR) applications. However, not all mobile AR tasks can be finished on mobile devices. Meanwhile, the limited computation resources on mobile devices are still the main obstacle to achieve realtime mobile AR applications. In this paper, we proposed a smart-decision framework which combines the advantages of the on-device mobile AR system and the edge-based mobile AR system to achieve real-time object recognition. High computation complexity tasks will be offloaded to the edge servers. Low complexity tasks will be executed on mobile devices or the edge server depending on the network latency. To overcome the dynamic changes of network condition and the limitations of the on-device deep learning models, we design a cache and matching algorithm on the mobile devices to enhance the performance of the recognition tasks. With our proposed system, the quality of the mobile AR application is improved. The performance of the smart-decision framework is validated through experiments with a testbed.