Formic acid has gained a lot of attention as one of the most promising liquid hydrogen storage carriers. Designing efficient and cost-effective heterogeneous catalysts for formic acid dehydrogenation can effectively address the challenges of in-situ hydrogen production, storage and transportation. In this study, the Au0.4Pd0.6Pt0.2 alloys with an ultrafine size (∼2nm) were prepared on amino-modified cellulose nanocrystals (CNC) with a total metal consumption of only 0.01mmol. The interaction between the support and nanoclusters provided the stable local environment for the catalysts, which showed remarkable HCOOH catalytic performance at low metal dosage, with TOFinitial of is 4478 h−1 and an Ea of 54.06kJ mol−1 at 323K, and the selectivity of hydrogen is 100%. Density functional theory (DFT) calculations demonstrated that the optimized local electron environment facilitated the OH bond cleavage and reduced the binding energy barrier between H*. This finding is beneficial to the development of more effective catalysts in the future.