Abstract: A crane hydraulic system and a controlling method of the system is provided in order to fundamentally reduce impact in start and stop operations of a load sensing winch system. The load sensing subsystem is arranged, at the start and stop moments of a winch system, the pressure compensator can be opened, and the variable pump oil inlet line communicates with the oil return line to realize pressure relief, so as to reduce the pressure impact.

Abstract: The present application relates to a crane hydraulic system and a controlling method of the system, wherein the crane hydraulic system includes a load sensing subsystem, and the subsystem includes a variable pump, a variable pump oil inlet line, a load feedback line, an oil return line and a pressure compensator; the pressure compensator is provided with an oil inlet, an oil outlet, a first control oil port, a second control oil port and a control spring; the oil inlet communicates with the variable pump oil inlet line, the oil outlet communicates with the oil return line, the first control oil port communicates with the load feedback line, and the second control oil port also communicates with the variable pump oil inlet line; and wherein the control spring and the first control oil port are located on the same end of the pressure compensator, and a set pressure of the control spring is greater than a pressure difference of the variable pump.