Objective To establish a quality control method for detecting impurities in chloral hydrate raw materials, improve the quality standards and control limits of raw materials. Methods The determination methods of chloroform and halogenated carboxylic acid in chloral hydrate were established to monitor the change of impurities in chloral hydrate through stability. Results The research and establishment of chloroform and halogenated carboxylic acid methods met the requirements of relevant regulations for analytical methodology verification, which could accurately detect four impurities in raw materials and preparations by one method. Conclusion The study provides technical support for the improvement and optimization of the quality standards of chloral hydrate and preparations. It is very necessary to implement the impurity monitoring in preparation research and production process by the chloral hydrate impurity detection and the stability comparison of this product at high temperature and light, which could largely promote the safety of medication.