Calcium sulfate whisker and magnesium sulfate whisker as reinforcer,SBS as toughener,ABS as resin matrix were used for manufacturing modified ABS composite by melt mixing and extrusion.The mechanical and thermal properties of the composites were tested,and the influences of calcium sulfate whisker and magnesium sulfate whisker usage on mechanical and thermal properties of the composites were observed.The toughening mechanism of the modified ABS composites was discussed,and the microstructure of the composite was observed.The test results showed that magnesium sulfate whisker had better comprehensive mechanical properties as compared with calcium sulfate whisker,when ABS was modified.