Valerate esters as a new class of cellulosic transportation fuels showed great industrial prospect. Here we developed a non-noble Ni/HZSM-5 bifunctional catalyst with excellent stability for the cascade transformation of levulinic acid to valerate esters. The acidity-regulation of Ni/HZSM-5 catalyst by potassium addition decreased the strong acidity, meanwhile tuned the proportion of Bronsted acidity/Lewis acidity. Coke analysis indicated that acidity-regulation by potassium addition changed the heavier coke component (alkylated poly-aromatics) to the lighter one (alkylated mono-aromatics), thus effectively prolonged the lifetime of Ni/HZSM-5 catalyst in fixed-bed reactor. The relationship of the nature of coke deposits and the acidity-regulation of catalysts could contribute to intensively understand the catalyst deactivation and the choice of stable catalyst for upgrading of biomass and its platform molecules. (C) 2016 Elsevier B.V. All rights reserved.