Arsenic, a toxic chemical element, is detrimental to environment and human health in particular. Therefore, the development of simple, fast, and accurate arsenic ion (As3+) detection methods has attracted extensive attention. In this work, an electrochemical sensor based on molecular imprinted polymer (MIP) and nano-porous gold (NPG) modified indium tin oxide (ITO) electrode (MIP/NPG/ITO) was developed for determination of As3+ in water with different quality. NPG with high conductivity, large specific surface area and high biocompatibility was prepared in situ on ITO surface by a green electrodeposition method using simple and controllable steps. Then, a layer of MIP was synthesized in situ on NPG surface by electropolymerization, in which As3+ was used as a template molecule and mphenylenediamine as a functional monomer. The preparation process of MIP/NPG/ITO was monitored by scanning electron microscope (SEM) and energy-dispersive X-ray spectroscope (EDS). The potassium ferricyanide and potassium ferrocyanide chelates were used as electrochemical probes to generate signals. The electrochemical behavior of MIP/NPG/ITO was studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). After optimizing the experimental conditions, As3+ was quantitatively detected by cyclic voltammetry. The linear range of As3+ was measured from 2.0 ×10-11 to 9.0×10-9 mol·L-1, and the lower detection limit was 7.1×10-12 mol·L-1 (S/N = 3). The detection limit of the constructed sensor is far below 10 ppb, which meets the drinking water standards set by the World Health Organization (WHO) and Environmental Protection Agency (EPA). In addition, the sensor has the advantages of simple preparation, simple procedure of determination, good repeatability, excellent reproducibility and stability. It is worth mentioning that the prepared sensor has been successfully applied to the As3+ measurements of four water qualities, including landscape river water, groundwater, tap water and domestic sewage. It can be predicted that the reported simple and cheap sensor has potential practical applications in environmental monitoring, food analysis and clinical diagnosis.