The invention discloses a material conveying device for biogas engineering. The material conveying device comprises a conveying steel belt machine and a middle feeding device, the conveying steel beltmachine is slantly arranged between the top of a fermentation tank and the ground, and the middle feeding device is mounted on the top of the fermentation tank; and the upper side of a feeding bin isconnected with the upper end of the conveying steel belt machine, the lower side of the feeding bin is connected with a screw conveyor, and the lower end of the screw conveyor is arranged below the biogas liquid level in the fermentation tank. According to the material conveying device for biogas engineering, loose straws are conveyed through the steel belt machine, a baffle is arranged on the steel belt machine, uniformity of straw conveying is ensured, and the phenomena of straw stacking and jamming caused by ordinary belt conveying are avoided; the movement speed of a steel belt is controlled, the conveying quantity of the straws can be controlled, and the material conveying device is suitable for adjusting the feeding quantity of biogas engineering; and the straws and backflow biogasliquid ejected from a bin top ejecting pipeline are mixed in a middle bin and then enter the fermentation tank, sufficiency of solid-liquid mixing is ensured, and the phenomenon of solid crusting in the tank is avoided.