The invention relates to a parallel loading and conveying device for marine steel plates and profiles. The conveying device comprises horizontal conveying chain mechanisms and lifting conveying chainmechanisms, wherein every two lifting conveying chain mechanisms are arranged symmetrically at the left end and the right end, and the horizontal conveying chain mechanisms are connected and arrangedin the middle part in sequence in a head-to-tail manner. When in use, the device is capable of simultaneously conveying workpieces such as steel plates, profiles and the like, and has great versatility, so that not only are the types of conveying equipment in a shipyard reduced, but also the number of operators is reduced; and the device also has the characteristics of simple mechanism, easy maintenance, good stability and high reliability, so that the overall conveying efficiency of a pretreatment production line for the steel plates and the profiles in the shipyard is greatly improved.