The invention provides an SAPO-11 molecular sieve and a hydrocarbon isomerization catalyst, and preparation methods of the SAPO-11 molecular sieve and the hydrocarbon isomerization catalyst. The SAPO-11 molecular sieve two-time crystallization preparation method comprises the steps: dissolving a phosphorus source and at least one aluminum source in water, and stirring; then adding at least one template agent and at least one co-solvent successively, dissolving, then crystallizing for a first time, and thus obtaining a solution after crystallization; adding at least one cationic surfactant and at least one silicon source into the solution after crystallization, aging, and crystallizing for a second time; cooling the crystallized product, centrifugally separating, washing, and drying, to obtain a cascaded-pore SAPO-11 molecular sieve raw powder; and roasting the cascaded-pore SAPO-11 molecular sieve raw powder in an air atmosphere, to obtain the SAPO-11 molecular sieve. The invention also provides the SAPO-11 molecular sieve obtained through the preparation method. The invention further provides the hydrocarbon isomerization catalyst with the SAPO-11 molecular sieve as a carrier and the preparation method thereof.