Based on microwave technology, a safe, energy-saving and intelligent system is designed to perform online detection and control for sugar crystallization. This online detection and control system, with embedded operating system, is equipped with an embedded microprocessor and ZigBee wireless sensor networks. With the benefit of this system, automatic production machinery of sucrose can work reliably in workshops which are in bad working condition. Furthermore, in sucrose crystallization process, real-time online detection and control for parameters like supersaturation can also be improved. Automation of sugar boiling becomes feasible and quality of refined sugar will be raised to a higher level due to this intelligent system.