The invention relates to a novel anaerobic reactor which comprises a reactor, a gas-collecting hood support, a reflective plate, a water distributor, a three-phase separator, a cross water-collecting tank, a ladder stand, a water-sealed tank, an embedded pipe, a drain pipe, an overhaul hole, an adjusting pond water inlet pipe, a sludge pump connecting pipe, an emptying valve and an oxidation ditch connecting pipe, wherein the ladder stand is spirally connected with the surface body of the reactor by means of fixed connection, the gas-collecting hood support is fixedly connected with the upper half part of the inner wall of the reactor, the adjusting pond water inlet pipe is L-shaped and is connected with an inner cavity of the reactor by means of fixed connection, the reflective plate and the water distributor are connected with the adjusting pond water inlet pipe in a sleeving manner, the gas-collecting hood support is connected with the top end of the reactor by means of fixed connection, and the cross water-colleting tank is connected with the reactor by means of fixed connection. The novel anaerobic reactor provided by the invention is stable in operation, simple to operate, relatively low in height, and can be used for producing biogas by using flocculent sludge and can save investigation.