Abstarct: Titanium mextal and its compounds play an important role in the economy and various industries of the country due to their special electrical, mechanical, optical properties and chemical and thermal stability. One of the processes of extraction and enrichment of ores containing titanium, is hydromextallurgical methods including sulfuric acid or hydrochloric acid, which are very important because they do not require a lot of energy. Therefore, the aim of this research is hydromextallurgical recovery and enrichment of titanium mextal from ilminite ore in Sabzevar region using chloride method and optimization of parameters affecting it. To achieve this goal, the sample obtained using the chloride leaching process was implemented on the obtained concentrate and finally the behavior of the effective parameters including acid concentration, liquid to solid ratio, temperature, stirring cycle and leaching time using the response surface method and the central compound design was investigated. the results showed that with the increase in temperature and liquid-to-solid ratio, the amount of recovery and grade of titanium dioxide increased, and the changes in acid concentration, stirring cycle and leaching time were parabolic, so that in their upper and lower levels, the amount of recovery and the grade of titanium dioxide decreased. Among the examined parameters, temperature and liquid to solid ratio respectively had the greatest effect on the recovery and volume of titanium dioxide. The optimization of the process was done and the best leaching mode was obtained at 5.13 M acid concentration, 7.59 liquid to solid ratio, 400 rpm stirring speed, 90 °C temperature and 2.9 hours leaching time, under these conditions recovery 61.81 and the grade of titanium dioxide was 19.85.