The invention provides a cast steel material with high strength, good toughness and low cost. The cast steel material is composed of, in weight percentage, 0.32-0.40% of C, 0.25-0.45% of Si, 0.50-0.80% of Mn, smaller than or equal to 0.035% of P, smaller than or equal to 0.035% of S, 0.02-0.03% of N, 0.020-0.060% of Al, smaller than or equal to 0.10% of Mo, smaller than or equal to 0.05% of V, smaller than or equal to 0.20% of Ni, smaller than or equal to 0.20% of Cu, smaller than or equal to 0.25% of Cr and the balance Fe and inevitable impurities. According to the cast steel material, on the premise of not increasing the wall thickness and the section ratio of engineering vehicle axle housings and suspensions and not increasing the manufacturing cost, the strength and the toughness of the axle housings and suspension supports are improved, and therefore the bearing capacity can be improved; and according to finite element analysis, the thickness of castings of products can be reduced appropriately, the purpose of light weight can be realized, and the manufacturing cost can be lowered.