Abstract: As the seven basic units of the SI system have been defined by the basic physical constants, the measurement has entered the era of quantization. Relying on the stability and reproducibility of Rydberg atom, The microwave electric field measurement technology can realize high sensitivity and low uncertainty. It can be directly trace the microwave electric field to the frequency unit. We adopts AT-splitting measurement technique and superheterodyne measurement technique to realize the measurement of microwave electric field with the microwave frequency range of （1~40） GHz and the field strength range of 0.5 mV/m~10 V/m by use cesium atom vapor cell. This work will impact diverse areas like metrology, radar, terahertz communication and electromagnetic signal monitoring.

Key words: Rydberg atoms, Microwave electric field, Autler-Townes splitting (AT splitting)