A toughened plastic and its preparation method, with the toughened plastic being obtained by rubber-plastic blending of brittle or less brittle plastics and a rubber mixture. The rubber mixture consists of powdery rubbers having a cross-linked structure and an average particle size of not more than 0.50 μm, and at least one selected from the group consisting of unvulcanized rubbers and thermoplastic elastomers. The morphology and the particle size distribution of the rubber phase contained in the toughened plastic can be controlled by changing the particle size of the powdery rubbers having a cross-linking structure and choosing proper unvulcanized rubbers or thermoplastic elastomers. The toughened plastic has good toughness and processability while keeping better strength and stiffness.