The invention discloses a rectal suppository for anaesthesia. The preparation method of the rectal suppository comprises the following steps: taking dexmedetomidinehydrochloride and ketamine hydrochloride as raw materials, adding a certain amount of matrix, a surfactant, a diluent, a humectant and a bacteriostat, and performing matrix melting, mixing, membrane injection, cooling shaping and packagingseparately. The rectal suppository does not require building a special administrationchannel, is directly dosed through arectum, avoids the liver first pass effect, takes effect quickly and is good in effect; the melting temperature of the rectal suppository is between 32EDG C to 35 EDG C, not only is beneficial to product storage, but also does not affect melting of the rectal suppository during use, meanwhile, the content of the rectal suppository is uniform and stable, A plus 1.8S of multiple products is smaller than 8, the product stability is good, the shelf life reaches 24 months, the increment of impurities is small during storage, the preparation process is simple and practical, and the rectal suppository is worthy of market promotion.