The invention discloses material grates for a biomass boiler. Each material grate comprises a substrate; a plurality of inclined ash guiding pieces are arranged on the lower surface of the substrate at intervals, the inclined angle a between each ash guiding piece and the substrate is 45-60 degrees, and an interval between two adjacent ash guiding pieces is 20-35 cm. After the material grates are mounted in the boiler, biomass fuel can fall onto the next layer of material grate along the ash guiding pieces, since the ash guiding pieces are mounted in an inclining manner, the biomass fuel can be overturned during falling, such that the biomass fuel can better make contact with air and is more sufficiently burnt, and the burning efficiency of the biomass fuel is greatly improved.