In order to improve the accuracy Eschka method  mixture melting sample potassium rhodanide titration measuring chlorinum in coal, chlorinum occurrence in coal, the principle of Eschka method, primary reagent, test procedures and factors of influencing accuracy of chlorinity content were analyzed. The result showed that it was advisable to follow the key steps and attention when using Eschka method to measure chlorinumt in coal, coal samples and Eschka should be fully stirred well and put to muffle, the temperature from indoor temperature to 680℃, burned more than 3 h at 680℃, boiling water leaching was adopted after cooled, with a neutral qualitative filters, the filtrate volume should be controlled in 110 mL or so, potassium rhodanide titration, chlorinum measurement in coal was settled based on the consumption of potassium rhodanide. The technology improved the test accuracy and coal use in industry.