Abstract: Q390 steel exists certain cold crack tendency during weld. For Q390 steel structure having larger cabined stress, the factors of affecting hydrogen induced cracking of important bearing steel structure need to be studied. Hydrogen induced cracking is caused by diffusible hydrogen during weld, so the glycerol test was used to measure diffusible hydrogen content of Q390 steel welded metal, and the effects of different conditions including different humidity and different types of filler metal were compared and analyzed. Results show that under same humidity, diffusible hydrogen content in metal welded with solid wires is significantly smaller than that with flux-cored wires; under large humidity, the increase tendency of diffusible hydrogen content in the metal welded with flux-cored wires is less than that with solid wires due to the joint protection of slag and gas; the view of diffusible hydrogen content in the metal welded with fluxcored wires is more than that with solid wires, and so they should be used to weld the position of bearing steel structure which has a small restrain intensity, and filler metal must be dried before use.