The invention provides a Mo-V-Te-Nb-O catalyst, a preparation method and application thereof. The catalyst takes ammonium molybdate, vanadyl sulfate, telluric acid and niobium oxalate as raw materials, and comprises the active ingredients of Mo, V, Te and Nb in a molar mixture ratio of 1:0.2-1.0:0.2-1.0:0.1-0.5. The method comprises the steps of preparing the ammonium molybdate, the vanadyl sulfate, the telluric acid and the niobium oxalate into mixed solution according to the mixture ratio, placing the mixed solution in a specially-made stainless steel reactor, raising the temperature from room temperature to between 160 and 230 DEGC through a program at a heating rate between 2 and 10 DEG C per minute, preserving heat for 2 to 20 hours, naturally cooling to room temperature, aging, taking out, performing pumping filtration, drying, roasting, grinding the obtained product to be 20 to 40 meshes and obtaining the catalyst. The Mo-V-Te-Nb-O catalyst prepared by adopting a temperature-programmed hydrothermal synthesis method shows high catalytic activity, catalyst stability and acrylic acid selectivity in reaction for preparing acrylic acid through propane selective oxidation.