Abstract: For the propose of finding high energy mid-infrared laser output,a compound cavity kalium titanyl arsenate(KTA) optical parametric oscillator(OPO) pumped by an electro-optic Q-switched flash-lamp-pumped 1064nm Nd:YAG laser was experimentally studied.Single pulse energy of 36mJ of the OPO was obtained at a repetition rate of 1Hz,where the idler pulse energy was 11mJ at 3407nm wavelength with pulse width of 10ns.The pulse energy decreased with increasing the repetition rate within the range of 5Hz~40Hz.The experimental result shows that the compound cavity pumping technology has the advantage of enhancing conversion efficiency and reducing oscillator threshold.With a mid-infrared image apparatus illuminated by the OPO,the laser spot was observed from the monitor of the image system.This result is useful for mid-infrared laser study.