In this work, we modified the single layer graphene by nitrogen modification through the low-damage plasma treatment (LD-plasma). The electronic transport characteristics for different modified parameters under aqueous environment were performed by Agilent semiconductor analysis B1500A. We choose potassium chloride (KCl) as our electrolyte. Based on the experimental results, the Dirac point is shifted linearly with the concentration of KCl. At the same time, the experimental results also show that the behaviors of 1-min and 3-min modifications are quite different between each other because of modification to graphene structure. As a consequence, this work shows an opportunity of being an ionic sensor with the developed nitrogen-doped graphene.