Abstract: A new fully automatic sounding system of middle atmosphere which succeeded in employing GPS positioning of 1680 MHz telemetry system has been introduced. Composed of balloon-borne sensors as well as ground tracking and signal processing equipments, the system has replaced the original radar or theodolite with GPS to track the radiosonde with no limitation of low elevation angle. Meanwhile, wide lobe antenna and low-noise receiver have been utilized to avoid losing the target. With this sounding system, the atmospheric electric field sounding experiments were conducted and satisfactory results have been obtained. Attributing to its portability, easy operation, low cost and favorable maneuverability and reliability, this sounding system is quite prospective for application in the near space environment detection, middle atmosphere scientific experiments and conventional meteorologic sounding as well.