Many teachers in elementary school utilize “reward cards” to maintain class order. However, the procedure of the card operations is trivial and the statistics of cards is also time-consuming. They increase the burden of teachers. In this paper, a real-time mobile reward cards system, called “Honor Bank”, is designed and expected to substitute the current paper reward cards. The “Honor Bank” is developed to be operated on the mobile devices with wireless communication to support classroom management. Its effect is also studied in this paper. Students of a class in fourth grade are selected to attend the experiment of “Honor Bank”. The results show that the positive behaviors are much more than the paper reward cards no matter if the student is male or female. But there is no obvious improvement in the math achievement. The experiment period may be too short and could be studied further.