The invention discloses a preparation method of a high-strength composite material with a silkworm cocoon structure. The preparation method comprises the following steps that the ends of natural silkworm cocoons are cut off, and then the residual parts are split in the radial direction to obtain square silkworm cocoon pieces consistent in size; each square silkworm cocoon piece is sheared along two opposite sides at intervals to form openings having a certain length, and a silkworm cocoon 'standard piece' having multiple tentacles on two sides are made; the multiple silkworm cocoon 'standard pieces' are spliced in the tentacle direction to form silkworm cocoon strips having a certain length; the multiple silkworm cocoon strips are spliced by using the silkworm cocoon 'standard pieces' to form complete large-area silkworm cocoon pieces; an odd number of silkworm cocoon pieces are laid and stacked, and every two adjacent layers of silkworm cocoon strips are mutually perpendicular in arrangement direction; finally, a bonding agent is applied to the stacked material, and then hot-pressing forming is performed to obtain the high-strength composite material with the silkworm cocoon structure. According to the preparation method, the natural silkworm cocoon structures are retained, a skin spinning process is not needed, the preparation method is simple and low in cost, and the obtained high-strength composite material with the silkworm cocoon structure is good in mechanics property and can be used as a reinforcing and protective material.