The present invention provides plastics with high toughness and the preparation thereof. The plastics with high toughness, which have the balance of stiffness and toughness, stable properties and good processability, are obtained by blending the rubber particles having an average particle size of 20 to 200 nm with the pseudoductile plastics, wherein the weight ratio of the rubber particles to the plastics is from 0.5:99.5 to 70:30. The present invention also provides plastics with both high stiffness and high toughness and the preparation thereof. The plastics with both high stiffness and high toughness, which have also an improved heat resistance and good processability, are prepared by blending the rubber particles having an average particle size of 20 to 500 nm and the crystalline plastics, wherein the amount of the rubber particles added in the plastics matrix is from 0.3 to 5 weight parts.