An integrated method and system for chlorine dioxide production coupled with a relatively independent electrolytic sodium chlorate production unit is disclosed. The system is consisted of the following features: an electrolytic production unit of sodium chlorate (NaClO3) and crystallization unit, a chlorine dioxide (ClO2) production unit and a hydrochloric acid (HCl) synthesis unit. The system feeds an electrolyte solution into a solid-liquid filter, wherein the electrolyte solution contains sodium chlorate crystal, to filter out the crystal from sodium chloride and sodium dichromate. The sodium chlorate crystal is then fed into a chlorine dioxide generator after dissolving, while sodium chloride and sodium dichromate solution separated returns back to the electrolyzer for the electrolysis process, recycling the intermediate chemicals in the sodium chlorate production system, rather than entering chlorine dioxide production unit. Whereas sodium chloride constantly formed as a byproduct in the chlorine dioxide
