The invention discloses a molecular sieve catalyst for preparing propylene by propane dehydrogenation and a preparation method of the molecular sieve catalyst, and belongs to the field of preparationof catalysts. The catalyst consists of a component A and a component B, wherein the component A is one of metal elements Sn, Ga, Fe, Co, Ni or Zn, the use amount of the component A is 1-9wt% of the total amount of the catalyst, the component B is a molecular sieve carrier, and the use amount of the component B is 90-99wt% of the total amount of the catalyst. The preparation method of the catalystcomprises a direct hydrothermal synthesis method and an impregnation method. The high-performance alkane dehydrogenation catalyst is prepared by controlling the use amounts, the structures and the dispersity of active components, has the characteristics of simple preparation process, low price and no toxicity, and has the characteristics of good activity, high selectivity, high stability and the like when applied to preparation of propylene through propane dehydrogenation; and a new technical scheme is provided for development and preparation of a new-generation alkane dehydrogenation catalyst.