The invention discloses flaky bacterial-fertilizer granules using chicken manure as carriers and preventing underground pests and a preparation method thereof. The flaky bacterial-fertilizer granules are prepared by the following components in percentage by weight: 83.5%-80.5% of dried chicken manure, 12%-15% of chlorpyrifos, 2.5% of high-performance cypermethrin and 2% of bacillus licheniformis, wherein the total components are calculated by 100%. The flaky bacterial-fertilizer granules disclosed by the invention have the advantages that the single-grain stability is good, no organic matters such as stabilizers and binders and the like are used, the environmental burden is reduced and the production cost is low; after buried into soil along with seeds or seedlings, the preparation absorbs water under a wet environment to expand, the soil moisture is maintained, and the nutrient components in the chicken manure are supplied; by utilization of the bacillus licheniformis, the soil structure can be improved, the use amount of fertilizers can be reduced and the effective components of pesticide can be slowly released; and the flaky bacterial-fertilizer granules have longer-time preventing effect for harmful pathogens such as underground pests and root-knot nematodes and the like.