Abstract: Taking wollastonite as raw material，aluminium sulfate and water glass as coating modifiers，a new type nano-aluminium silicate-wollastonite composite was obtained by the chemical depositing method. By modifying this composite powder with amino-silane and filling it in PP，the polypropylene composite was obtained. The composite and modified powder were characterized by SEM，BET，grain size analyser，whiteness apparatus，XRD，EDX and FTIR. The mechanism of composite powder modified by amino-silane was discussed. The results show that the surface of wollastonite is coated with nano-aluminum silicate evenly，the whiteness is increased from 90.5 to 92.5，the specific surface area is increased from 1.41 m²/g to 4.78 m²/g，and the average grain size of aluminium silicate is 54 nm. Filling 40 wt% modified composite powder in PP，the tensile strength，bending st rength and heat distortion temperature of the material have been increased from 17.81 MPa to 21.97 MPa，from 23.72 MPa to 39.20 MPa and from 65.7℃ to 94.3℃，espectively.