In this paper, we described the reliable message transmission system based on MQTT protocol and experimented to ensure fast message delivery and guarantee the ordering of messages for IoT environment. We had the experiment confirmed the reliable message transmission system can deliver the messages sequentially without a long time delay by using a mobile device. We expect that the experiment by using IoT device shows same result because both of a mobile device and an IoT device is very similar. The reason why these are similar is that both of a mobile devices and a IoT device are small and movable device and has to be worked under low-power and unreliable network condition. In near future research, we will design and implement the collaboration messenger system to be worked on IoT environment such as a home control IoT device and a mobile device. A IoT device for home control is needed accurate message transmission to mobile device for sending exact message to control home equipment. Also, we will implement IoT device by using a Raspberry-pi and have experiment how messages will be transmitted exactly between IoT devices and mobile devices.