The invention discloses low-cost high-machinability steel for an engineering machine and a manufacturing method of steel. The steel comprises components including, by weight, 0.06% to 0.10% of C, 0.30% to 0.60% of Si, 1.00% to 1.60% of Mn, not larger than 0.015% of P, not larger than 0.0030% of S, 0.20% to 0.60% of Ni, 0.50% to 0.80% of Cr, 0.25% to 0.55% of Mo, 0.025% to 0.065% of V, 0.0008% to 0.0020% of B, 0.008% to 0.018% of Ti, 0.030% to 0.070% of Al, not larger than 0.0050% of N, 0.0010% to 0.0040% of Ca, and the balance Fe and inevitable impurities. Mn/C is larger than 15, {steel plate quenching temperature*[(%Cr)+3.3(%Mo)+1.75(%V)+2.15(%Si)]}/[11.7(%C)<1/2>+1.23(%Mn)+0.36(%Cu)+(%Ni)] is larger than or equal to 415 and smaller than or equal to 565, Ca/S ranges from 0.80 to 1.50, and (%Ca)*(%S) is larger than or equal to 2.5*10<-6> and smaller than or equal to 2.5*10<-3>. Controlled rolling and two-phase-area quenching and tempering technologies are combined, high strength is obtained, and meanwhile, low-temperature toughness, cold machining moldability, welding performance and fatigue-resisting impact load properties of a steel plate are also excellent.