Plasma activated water (PAW) is produced through the interaction of water with plasma that contains a large number of active species. PAW has been widely used in sterilization, agriculture, and medical treatment. In this study, an array plasma jet composed of 6 DBD reactors was utilized to activate water. The pH value, conductivity, temperature, and total residual oxidants (TRO) were measured to characterize the PAW generated by the plasma jet under different treatment times, gas flows, and storage durations. Optical emission spectra (OES) of the plasma jet were recorded. The performance of E. coli inactivation was investigated. The results demonstrated successful generation of PAW using the array plasma jet. It was observed that the pH value decreased rapidly within several minutes and remained relatively stable during prolonged treatment periods. The conductivity and concentration of TRO increased significantly with the treatment time increased. The inactivation efficiency could be as high as 99.9999% when the PAW prepared by array plasma jet with 20 min treatment. Both the pH value of PAW and concentration of active species had a significant impact on its inactivation efficiency. The PAW had very high inactivation efficiency when it was used immediately after preparation, and it still had a certain sterilization ability with long storage time, which was of important for the application of PAW. The OES suggested that active species such as excited molecules, ions and radicals were produced in the air plasma jet. The active species were the origin of PAW generation, and the reactive oxygen and nitrogen species were responsible for the inactivation of E. coli.