A multi-structure needle-ring electrode argon plasma jet device was designed to grasp the quantitative influence of the reactor structure parameters and discharge parameters on the jet length of the atmospheric pressure non-equilibrium plasma jet (N-APPJ). The effects of discharge voltage, electrode gap, the distance between the discharge end of the high-voltage electrode and the ground electrode, and the volume flow of argon on the jet length were calculated. The results show that the maximum length of the plasma jet can reach 80mm; the longer the distance between the discharge end of the high voltage electrode and the ground electrode, the longer the jet length but not linearly; the jet length first increases and then decreases with the increase of the electrode gap, and the jet reaches the maximum length when the electrode gap is 4.5 mm; with the increase of the volume flow of argon, the length of the plasma jet also shows a trend of first increasing and then decreasing, and the decreasing amplitude is low; the electron excitation temperature It is higher at the high-voltage electrode and the ground electrode, and the part between the two electrodes is second, and there will be a more obvious drop at the outlet of the quartz tube.