The invention provides an iron-based amorphous nanocrystalline laser cladding composite coating, a preparation method and a test method. The cladding composite coating meets a molecular formula: FeaCobNicBdSiyNbe, wherein a, b, c, d, y and e represent the corresponding alloy element atomic percent: a is larger than or equal to 32 and less than or equal to 44, b is larger than or equal to 10 and less than or equal to 15, c is larger than or equal to 10 and less than or equal to 15, d is larger than or equal to 18 and less than or equal to 20, y is larger than or equal to 4 and less than or equal to 23, e is larger than or equal to 4 and less than or equal to 5, and a+b+c+d+y+e is equal to 100. The preparation method comprises the preparation steps of weighing the raw materials, mixing the raw materials to obtain alloy powder, pretreating a base plate, flatly spreading the alloy powder to the surface of the base plate, and using a laser beam to perpendicularly laser-clad the alloy powder. The composite coating has a certain amorphous content, high microhardness, excellent abrasive resistance and outstanding breaking strength; and the preparation process is simple, and the raw materials do not contain rare earth or volatile elements, so that the iron-based amorphous nanocrystalline laser cladding composite coating has broad application prospects.