The invention discloses a method for pressing a steaming-free and baking-free wall body block from dehydrated sludge in a sewage treatment plant. The method specifically comprises the following steps:dehydrating sludge of the sewage treatment plant, modifying the dehydrated sludge by virtue of seashell dust, ferrous sulfate and calcium hydroxide, so as to obtain modified sludge; mixing the modified sludge, the seashell dust, calcium sulfate, silica fume, slag charge, an F14 liquid activating agent and water, so as to obtain a mixture; digesting the mixture, so as to obtain a digested material; mixing the digested material, a solidifying agent and a YW-type surfactant, so as to obtain a blank preparing material; preparing a product workblank from the blank preparing material by virtue of apunching system; and carrying out pre-maintenance on the product workblank, and carrying out thermal air circulating reaction maintenance on the product workblank, so as to obtain the wall body block. The method has the beneficial effects that the problems in the effective treatment and resource utilization of the dehydrated sludge and industrial waste residue or engineering muck in the sewage treatment plant are solved, the cost is low, an obtained baking-free brick has excellent compressive strength, has no radioactivity, can be used for producing multiple specifications of wall body blocksand can be manufactured into building components for various uses.