A biodecomposable film material includes: a biodecomposable material which is one or more selected from the group consisting of polylactic acid, poly(butylene adipate-co-terephthalate) and poly butylene succinate and which has a mass percentage of 60-70%; a food grade agricultural waste having a diameter smaller than 50 μm and a mass percentage of 10-30%; a modifier which is calcium carbonate powder or magnesium silicate salt powder and which has a diameter smaller than 8 μm and a mass percentage of 7-29%; and an organic decomposing bacterium which is Bacillus amyloliquefaciens. The organic decomposing bacterium is heat resistant bacillus capable of withstanding a temperature of 100° C. and has a mass percentage of 1-3%. The biodecomposable material, the food grade agricultural waste, the modifier, and the organic decomposing bacterium are subjected to compounding and blowing to form a film having a thickness of 40-60 μm.
