Abstract: In the process of aquatic products drying, there are problems of dewatering too fast on the surface and water spread passage blocking, which cause high moisture unevenness and affect the product quality after drying. For solving the problems, authors designed a U-shaped tunnel-drying room for aquatic products. Some key techniques were analyzed and studied, which contains cross flow drying, switching forward and reverse airflow, on-line controlling of temperature and humidity of drying medium and circulating use of heat energy etc.. Compared with single as well as double passageway drying room, evenness of hotting air temperature in U model tunnel was improved, utilization ratio of heat energy was increased, drying time was cut down, and the output of unit volume was increased. The spot experiment of drying grass carp stated that moisture content of products were well distributed after drying, heat energy can be saved about 30% and drying time can be cut down approximate to 30%.