Abstract: A low cost microwave detector experimental device is designed in this paper.By setting a common digital multimeter to “mV” range as the indicator, the dynamic range of detected microwave signal is over 58 dB in a frequency range of 10 MHz~3 GHz.Conducting antenna experiment with the detector instead of valuable instruments such as microwave spectrum analyzer will reduce the cost of experiments.And it is proved that the measuring range and accuracy can meet requirements of experiment in education, and can effectively control the experiment cost.