Composite toughened polylactic acid degradable master batch as well as preparation method and application thereof

The invention provides a composite toughened polylactic acid (PLA) degradable master batch as well as a preparation method and application thereof, and relates to the technical field of degradable PLA wood-plastic composite materials. Comprising the following preparation raw materials in parts by mass: 20-60 parts of PLA resin, 10-50 parts of modified plant short fibers, 10-50 parts of modified CaCO3 particles and 0.5-1.0 part of a lubricant. Aiming at the problems that PLA is poor in flexibility and impact property and high in cost, plant short fibers and CaCO3 particles are modified by adopting an interface modifier, so that the problem that the strength of PLA is reduced while the toughness of the PLA is improved by using the plant short fibers or the CaCO3 particles due to the fact that the plant short fibers and the CaCO3 particles are difficult to disperse in the PLA and the interface compatibility is poor is effectively solved; and the cost of the PLA composite degradable master batch is reduced. The c