The invention discloses a polylactic acid material with a high stereocomplex crystal content and a high molecular weight, and a preparation method thereof. The polylactic acid material is prepared from, by mass, 2-6% of poly-L-lactic acid, 2-6% of poly-D-lactic acid, 1-3% of epoxy resin, 0.05-0.6% of an amine curing agent and 84.4-94.95% of trichloromethane. Compared with the prior art, the methodhas the advantages of simple process in block copolymerization, chain chemical topology design and crystallization condition control, and low production cost.