The invention discloses a passive beacon device used for microwave interception. The device includes an interception end radar, a collection end antenna, a power divider, a rectification filter circuit, a pickup device and a frequency mixer. A carrier wave with high energy is emitted by the interception end radar, and the carrier wave with high energy is received by the collection end antenna andis transmitted to the power divider; alternating current energy is extracted from the carrier wave with high energy through the power divider, the alternating current energy is converted into direct current energy through the rectification filter circuit, and the direct current energy provides energy for a microwave interception beacon source device; the pickup device and the frequency mixer are used for pickup work with high quality, and modulation of a sound electric signal and the carrier wave with high frequency. The probability of the device being intercepted is reduced, the interceptioneffect is improved, and the requirements of long time disposition using are satisfied.