MQTT is a lightweight protocol based on publish/subscribe messaging transport. It provides a new way for message push on Android. For the demand of message push protocol on Android, analyzed the structure of MQTT and the format of its message, and compared with other message push solutions on the Android platform. Then, designed and implemented an instant messaging application based on the MQTT protocol. Has finished many functions such as login/register, send instant message, manage friends and so on. Finally, the test result indicated that this application is satisfy the basic functionality and requirements of the instant messaging applications.