The invention relates to a medical apparatus. Provided is a hemodialysis online dry powder barrel, including a barrel body. The bottom of the barrel body is provided with a liquid outlet. The barrel body is internally provided with a filter screen which filters liquid flowing out through the liquid outlet. The barrel body is detachably connected with a barrel cover in a sealed manner. The barrel cover is provided with a liquid inlet. The invention provides the hemodialysis online dry powder barrel which reduces possibility that dry powders are polluted in dry powder solution preparation, and solves a problem that preparation of an existing manual open dry powder solution is easily polluted.