The utility model discloses a water-saving and energy-saving non-agitation horizontal methane tank, comprising a fermentation pool body, wherein the fermentation pool is connected with a molded glass fiber-reinforced plastic combined head cover and reinforced by waterproof anti-seepage concrete sealant; the fermentation pool is partitioned into a plurality of small fermentation rooms by glass fiber-reinforced plastic reinforcing plates; a solar hot-water circulation pipe is arranged inside the first fermentation room near a feeding pipe, so that feed liquid is rapidly heated up; the heated feed liquid is swirled and mixed evenly in each small fermentation room under the action of a water pressure difference; the fermented slag liquid is automatically discharged into a storage pool; the participated liquid is sprayed to each small fermentation room by using a circulating pump; the feed liquid is more evenly mixed; the liquid also can be circulated to a feeding pool to be mixed and utilized with a fresh material through a liquid circulating pipe. The feed liquid disclosed by the utility model does not need to be stirred by an agitator, so that the water-saving and energy-saving non-agitation horizontal methane tank is low in operating cost, capable of fermenting the feed liquid thoroughly, and high in gas generation rate, and the feed liquid is recycled, so that water and energy are saved, and the environment is protected.