The utility model relates to a hydrolytic polymaleic anhydride continuous production device, and belongs to chemical equipment. The adopted technical scheme is as follows: the method comprises the following steps of: preparing raw materials; the device comprises a mixing kettle, and a multi-stage polymerization reaction kettle, a hydrogen peroxide storage tank and a heat preservation reaction kettle which are connected in sequence, a discharge hole is formed in the lower part of the mixing kettle and is connected with a feeding hole of the primary polymerization reaction kettle through a pipeline; a discharge port of the n-stage polymerization reaction kettle is connected with a feed port of the n + 1-stage polymerization reaction kettle through a pipeline (n is greater than or equal to 1); wherein a feed port and a discharge port of each polymerization reaction kettle are arranged at the upper part of the polymerization reaction kettle, the feed port is higher than the discharge port,the discharge port of the last stage of polymerization reaction kettle is connected with the feed port of the heat preservation reaction kettle through a pipeline, the discharge port of the heat preservation reaction kettle leads to a finished product tank, and the top of each polymerization reaction kettle is provided with a top discharge port. According to the device, multiple stages of polymerization reaction kettles are connected in series in a stepped manner, and automatically overflow into the next stage of reaction kettle through the side ends of the reaction kettles, so that continuous production of hydrolyzed polymaleic anhydride is realized.