The invention belongs to the field of hydraulic steering techniques for double-drum rollers, and particularly relates to a lockable hydraulic crab steering system for double-drum rollers. The steering system comprises an oil tank, a hydraulic pump, a steering gear, a crabbing valve, a first crabbing cylinder, a second crabbing cylinder, a first steering cylinder and a second steering cylinder; after passing through the hydraulic pump, the steering gear and the crabbing valve, the oil in the oil tank is divided into a steering loop and a crabbing loop, and then flows back into the oil tank via the steering gear; the steering loop is connected in parallel with the crabbing loop; the crabbing valve comprises a two-position six-way electromagnetic reversing valve, a first balance valve and a second balance valve; the steering loop is connected with the two-position six-way electromagnetic reversing valve; and the crabbing loop is connected with the two-position six-way electromagnetic reversing valve respectively through the first balance valve and the second balance valve. The arrangement of the steering system is compact, steering operation and crab steering operation can be realized, moreover, the linear running of a double-drum roller can be guaranteed, and the efficiency of operation and the quality of rolling can be increased.