Disclosed is a hydraulic construction machinery capable of operating a travel apparatus and a swing apparatus, when same are to be operated in combination, by means of working fluids supplied at the maximum discharge flow rate from a plurality of hydraulic pumps. A hydraulic construction machinery according to the present invention comprises: first and second hydraulic pumps; travel and swing motors connected to the first hydraulic pump; a hydraulic actuator connected to the second hydraulic pump; a main control valve comprising a first control valve and a second control valve, the first control valve controlling a working fluid supplied from the first hydraulic pump to the travel and swing motors, and the second control valve controlling the working fluid supplied from the second hydraulic pump to the hydraulic actuator; a first regulating valve, disposed on the most upstream side of a supply channel of the second hydraulic pump, for switching when the travel and swing motors are operated simultaneously so that the working fluid of the first hydraulic pump is supplied to the travel motor and the working fluid of the second hydraulic pump is supplied to the swing motor; a second regulating valve, disposed on the most downstream side of a supply channel of the second hydraulic pump, for switching when the travel and swing motors are operated simultaneously so as to close the most downstream opening of the supply channel of the second hydraulic pump; and an electronic proportional valve for outputting a control signal, corresponding to a control signal from a controller, to the first and second regulating valves when a manipulation signal, sensing whether the travel and swing motors are manipulated, is entered in the controller.