A CW submillimeterwaveguide discharge－pumped DCN laser has been designed,which operates on 190μm and 195μm lines. The laser discharge length is 3m, and the resonator length is 3. 4m. The resonator cavitymaks up of a pyrex tube of 54mm diameter and two plane reflectors against its ends, one is a crystal plane mirror, the other is a metalmesh. With the op timization of various parameters, such as the gasmixture N2 ∶CD4 ∶He = 1∶3∶12, the gas pressure 206pa and the discharge current 1. 4A, the wall temperature 155℃, this laser delivers 200mW and 220mW on the 190μm and 195μm lines, respectively, for EH11 mode.