Diode pumped metastable rare gas laser (DPRGL) is a potential candidate for single aperture scaled extremely high energy lasers. In the current studies, the metastable atoms were generated in confined discharge gaps, which limited the high power output. In this paper, a DPRGL in a plasma jet is firstly proposed and demonstrated. A high concentration of metastable argon atoms (about 10¹⁴ cm^-3) is produced in the plume of an atmospheric plasma jet, which separates the discharge and gain regions. By using a 811 nm linewidth narrowed diode laser as pumping source, based on a “pump, laser and flow” mutually orthogonal configuration, the system realizes 912 nm laser output. The plasma jet type DPRGLs have the potential to break through the limitations of the existing schemes, and significantly improve the power scaling ability.