The synchronous observation of submicrosecond electromagnetic changes resulted from lightning is described. A newtype fast/slow rangeadjustable measuring system of electric field changes is developed. The equipment can be used to observe lighting in different environments in combination with magnetic measuring devices. The software of the system based on Labwindows/CVI with the PCI5105 card is discussed. The main advantages of this system include high sampling rate， high capacity， multiple parameters， and synchronous measurement. This system was used to observe lighting flashes and analyze lightning physical processes in a field experiment.