A novel method for the phase-shift control of an injection-locked magnetron with Virtual Instrument Software is presented to enhance the microwave power combining from injection-locked magnetrons. An automatic power combining operation and control module based on a LabWindows/CVI program is presented as well. A few functions, such as data collection, analysis, and feedback control, are realized with the module. The minimum phase shift step and the phase shift range are 5.6° and from -180° to 180°, respectively. The processing rate of the system reaches the order of milliseconds. It is shown that the module works well and the system is reliable according to experiments results.