Abstract: Ablative capillary discharge plasma jets are characterized by high density and relatively low temperature. The devices of this kind of plasma jets are of importance to a variety of applications. Two-gap capillary plasma generator(TGCPG) is a realistic alternative to the conventional capillary in electrothermal launchers and a versatile capillary plasma generator for other applications. A one-dimensional hydrodynamic model considers which the ohmic heating and wall ablation is proposed for calculating the properties of plasma arcs of the main discharges in TGCPG. The calculation shows that the discharge is in a quasi-steady state, the plasma temperature keeps stable during the discharge while the mass density and pressure are drastically changed. With 1 kJ discharge energy, a plasma jet wit