The invention discloses a low-emission low-smoke density natural fiber-improved composite packing box. The low-emission low-smoke density natural fiber-improved composite packing box comprises a box body and a box cover, and the box body and the box cover are made of low-emission low-smoke density natural fiber-improved composite plates; each low-emission low-smoke density natural fiber-improved composite plate is composed of a wear-resistant layer and a substrate from outside to inside, and each substrate is compounded from natural fibers and a PVC substrate; the box body comprises a protrusion I arranged in the middle of the box body and an annular edge I arranged at the periphery of the protrusion I; the box cover comprises a protrusion II arranged in the middle of the box cover and an annular edge II arranged at the periphery of the protrusion II; the section of the box body annular edge I and the section of the box cover annular edge II are both in a conical shape; and when the box cover protrusion II covers the portion, over the annular edge II, of the box body, the box cover annular edge II sleeves the box body annular edge I and is closely matched with the box body annular edge I. The low-emission low-smoke density natural fiber-improved composite packing box has the further improvement that the box body and the box cover are each provided with a sideslip preventing structure for stacking, and a handle extending outwards is arranged at one corner of the box cover annular edge II. According to the low-emission low-smoke density natural fiber-improved composite packing box, the natural fibers can be utilized on a large scale, the sealing property is good, stacking is convenient, no sideslip occurs, and use is convenient.