Abstract: A spring of 50CrVA steel was found to have fractured after service for a while. The fracture cause was analyzed by fracture observation, micro-structure examination, energy spectrum analysis, and microhardness testing. The results show that the failure mode of the spring is hydrogen induced brittle fracture, which was mainly caused by the electrical contact damage occurring during electric plating. In addition, excessive acidwashing during the process of decopperization is another factor for the hydrogen induced brittle fracture. The following measures can be taken to prevent thus failure. On the one hand, it should be ensured that spring thread don't contact the electric pole during electric plating. On the other hand, the hydrogen absorbed by the spring should be reduced during surface treatment and the dehydrogenation time should be prolonged.