Abstract: The multi-element Ni-Cr-Mo-Cu surface alloying layer on the matrix of low carbon steel 20 was investigated by means of the double glow plasma surface alloying technique. The results show that the technical parameters have obvious effect on the total content of alloyed elements and the thickness of the alloying layer. The optimum parameters of alloying Hastelloy C-2000 were obtained by the orthogonal test.