The carbon material derived from citrus peel was prepared via hydrothermal synthesis method with low amount of ZnCl₂. The morphology and surface structure of the synthesized carbons were characterized by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD) and N₂ adsorption/desorption isotherms measurements. The electrochemical and capacitive deionization performance of carbon materials were comparatively studied by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge (GCD). Compared with the materials activated with KOH or H₃PO₄, ZnCl₂-activated carbon showed the best electrochemical double-layer characteristics, with the specific capacity of 120 F g⁻¹. When being applied as anode in the capacitive deionization (CDI) cell, the desalination amount of 16 mg g⁻¹ and the average salt adsorption rate (ASAR) of 0.67 mg g⁻¹ min⁻¹ were achieved, which is much higher than those of KOH- and H₃PO₄-activated materials. The desalination amount retained 80% after 35 cycles. The possible mechanism is proposed in light of X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) analysis. This work provides a facile and environmentally friendly method for the preparation of a green and low cost biomass derived porous carbon material by fruit waste with a low amount (1% mass) of activation regents for high performance capacitive deionization.