The invention provides vanadium-contained 10.9-level steel for a fastener for rail transit mobile equipment. The steel mainly comprises following chemical elements including, by mass percentage, 0.33% to 0.38% of C, 0.05% to 0.10% of Si, 0.70% to 0.90% of Mn, 0.70% to 0.90% of Cr, 0.30% to 0.60% of Ni, 0.20% to 0.30% of Mo, 0.015% to 0.045% of Als, 0.03% to 0.06% of Nb, not larger than 0.010% of P, not larger than 0.005% of S and not larger than 0.0015% of T[O]. The autstenitic grain size of steel obtained after heat treatment of the fastener is larger than 10.0 level, and according to the structure of the steel obtained after heat treatment of the fastener, a small amount of small pro-eutectoid ferrite is dispersed and distributed on a tempered sorbite base body, wherein, the amount of the pro-eutectoid ferrite is smaller than or equal to 5%, and the size of the pro-eutectoid ferrite is smaller than or equal to 5 micrometers. The longitudinal mechanical property of the fastener obtained after heat treatment can meet the standard requirement.