The fabrication technologies of diffractive optical elements such as photolithography, thin-film deposition, direct writing, diamond turning, excimer laser etching, gray-tone mask and replication are summarized. The technology processes of the methods for fabricating diffractive optical elements are introduced in detail. And the advantages and disadvantages of the methods are analyzed. The applications of diffractive optical elements in spectral lens are introduced. The detailed design examples of diffractive surface in the waveband of visible, infrared and ultraviolet spectrum are described respectively. The conclusion shows that diffractive optical elements can help to increase design freedom, simplify system structure, reduce system volume and weight, and improve system astigmation and imaging quality.