The invention discloses a DOPO derivative modified organosilicon damping additive and a preparation method and application thereof. The structural formula of the damping additive is as shown in the formula I. in the formula I, R1, R2, R3, R4, R5, R6, R7 and R8 are respectively selected from C2-C5 alkenyl group, aryl group, halogenated aryl group, amino-group, C1-C5 alkyl group, C1-C5 cyanogen alkyl group, C1-C5 halogenated alkyl group and C1-C5 aminoalkyl group; R5, R9 and R10 are respectively selected from C0-C5 alkylene group; R11, R12, R13, R14, R15, R16, R17 and R18 are respectively selected from hydrogen atom, aryl group, halogenated aryl group, nitro group, C1-C5 cyanogen alkyl group, C1-C5 halogenated alkyl group, hydroxyl group, halogen and C1-C5 alkyl group; m is any integer from 0-200; n is any integer from 0-200; q is any integer from 0-200; and m, n and q are not 0 at the same time. The damping additive of the invention will not migrate in silicone rubber base, has good compatibility with silicone rubber, is efficient, is easy to add, and will not influence mechanical properties of silicone rubber.