The invention discloses a MoS2-SnO2-carbon fiber composite material and a preparation method thereof, wherein the preparation method comprises that a SnO2 nanometer material grows on a carbon fiber material in a coated manner and a MoS2 nanometer material is subjected to secondary growth at the SnO2-carbon fiber by using a two-step hydrothermal method. According to the present invention, during the hydrothermal preparation, any templates and catalysts are not required, and the method has advantages of simple process, high yield and low cost, and is suitable for mass production; and the MoS2 nanometer material directly grows on the SnO2 coated carbon cloth, and the prepared nanometer composite material has the sandwich structure, has characteristics of tight coating and clear layering, andcan be used as photocatalysis materials, electrocatalysis materials, solar cell materials, flexible sensor materials, field emission materials and lithium ion battery negative electrode materials.