Nitrogen ion implantation in Nimonic 80A using plasma immersion ion implantation (PIII) was investigated at a pulse voltage of -60 kV and ion dose of $3{ imes}10^{17}{sharp}/cm^2$, $6{ imes}10^{17}{sharp}/cm^2$, $12{ imes}10^{17}{sharp}/cm^2$. PIII is an effective technology to improve the surface hardness and wear resistance of materials. And also this technology is not limited by the shape and size of materials. PIII would be a promising technique in the future. Surface hardness and wear resistance of the $N^+$ ion implanted Nimonic 80A were increased with the increase in the incident ion dose. The surface hardness of the untreated Nimonic 80A is 420 Hv, the hardness of implanted Nimonic 80A is 1050 Hv at $N^+$ ion dose of $12{ imes}10^{17}{sharp}/cm^2$. The wear loss of the untreated is 82.5 mg, the wear loss of the implanted is 0.004g at $N^+$ ion dose of $12{ imes}10^{17}{sharp}/cm^2$. The $Cr_2N$ is detected on the surface of the implanted Nimonic 80A by XRD analysis.