Abstract: In this study, an automated testing system for a reflection-type Vector Modulators (VM) comprised of a Field Programmable Gate Array (FPGA) and a LabVIEW based testing software is presented. The testing system with a friendly Graphic User Interface (GUI) is able to evaluate all the functionality of the VMs and allows the user to test the FPGA module step-by-step or to automate the testing in a sequential way. In case of multiple VM testing, all the VMs can be tested in one time by automatically sending the control commands to manipulate the bias voltage of each VM. Only one FPGA based hardware is needed in the testing system for the bias voltage control. This present testing system is highly efficient for VM testing and can be easily generalized to the testing of other VMs.