Formic acid (FA) plays a key role in various chemical processes and industrial procedures. Attractively, FA can be produced from renewable biomass instead of fossil resources. In this paper, FA was successfully prepared with the help of isopolyacid Na6[α-Mo6V2O26] (Mo6V2), which is superior to Keggin-type heteropoly- acids containing vanadium because its stronger oxidizing ability endows Mo6V2 with better ability to break C-C bonds. Some carbohydrates and biomass, including glucose, fructose, xylose, hemicellulose, cellulose, corn stover, and birch, acted as sources to prepare FA in aqueous solution in the presence of Mo6V2. For monosaccharides, Mo6V2 can accelerate the reaction rate and obtain the highest FA yield of 62 % from xylose. For hemicellulose, the yield of FA reaches up to 54 % in only 8 min. In the case of insoluble biomass materials, the combination of p-toluenesulfonic acid (TsOH) and Mo6V2 can boost the catalytic performance of the system, with the FA yield being 47 % from cellulose, 37 % from corn stover, and 41 % from birch. Therefore, Mo6V2 can be valued as an universital and promising catalyst for transforming renewable waste biomass to high-value chemicals.