The invention provides a suspending device for a bridge detection working vehicle. The suspending device for the bridge detection working vehicle mainly comprises a rear axle steel plate spring suspension device, two or four supporting leveling base, an oil suspension device and a stander assembly; the rear axle steel plate spring suspension device consists of two groups of steel plate springs; each group of steel plate springs is formed by mutually overlapping and fixing a plurality of steel plates with different lengths; each supporting leveling base has a framework structure formed by welding a plurality of steel plates; the oil suspension device comprises a suspension oil cylinder, a supporting foot base, a U-shaped base, a connecting plate, a bidirectional hydraulic lock and a three-position four-way reversing valve; and the stander assembly comprises a chassis vehicle frame and an auxiliary vehicle frame. The steel plate spring suspension and the oil suspension are combined organically, so the suspending device for the bridge detection working vehicle plays a role in buffering and damping during running of the bridge detection working vehicle, and rigidly supporting during working of the bridge detection working vehicle; therefore, the contradiction of buffering and damping during running of the bridge detection working vehicle and rigidly supporting during working of the bridge detection working vehicle can be solved effectively. The suspending device for the bridge detection working vehicle has the characteristics of large bearing capacity, rational fixing position, high stability, low contact stress and high reliability.