The invention discloses a biodegradable high-barrier 
vacuum evaporation film base material and a preparation method thereof. A film is sequentially composed of a high-barrier 
coating layer and a biaxially-oriented 
polylactic acid (BOPLA) 
film base material layer from top to bottom, wherein the base material layer consists of an upper 
surface layer, a core layer and a lower 
surface layer. The preparation method comprises the following two steps: firstly, preparing a 
polylactic acid film (BOPLA) base material meeting the 
coating requirement by using a horizontal drawing method, and then formingthe high-barrier 
coating layer on the surface of the 
film base material by using an online coating process or an offline coating process. According to an aluminum-plated film and an aluminum 
oxide-plated film which are produced by utilizing the high-barrier 
vacuum evaporation film base material prepared by the invention, the optimal 
oxygen permeability can be less than 0.02 cc / m<2>.24h, and the optimal 
water vapor permeability reaches 0.05 g / m<2>.24h; and the high-barrier 
vacuum evaporation film base material not only has an excellent 
barrier effect, but also is biodegradable, can effectivelysolve the environmental problem caused by waste packaging films, and is high in 
industrial utilization value.