The flammability of lignocellulose poses a great challenge to its application in textile, architecture and decoration. In this paper, two kinds of deep eutectic solvents were used to modify lignocellulose, and then loaded with ammonium polyphosphate-alumina hydroxide (APP-ATH) double effect flame retardant to prepare flame retardant composites. The results showed that the modified lignocellulosic surface groups changed through FTIR spectra, and the surface of modified lignocellulosic was rough, and the amount of flame retardant loaded lignocellulose increased with the increase of flame retardant content in SEM images. Through cone calorimeter experiment, compared with pure lignocellulose, the flame retardancy of the LPA composites prepared by modified loaded flame retardants was obvious. The bending strength of choline chloride/cardano system was higher than that of choline chloride/ethylene glycol/oxalic acid system, and the bending strength of choline chloride/cardano system was higher than that of pure lignocellulose. This will make the application of lignocellulosic flame retardancy more extensive and in-depth.