A method for operating a hydraulic system of an industrial truck, wherein the hydraulic system comprises a first hydraulic pump, a second hydraulic pump and a hydraulic line system, the method comprising:
- selectively connecting, using the hydraulic line system at least one hydraulically operated component either exclusively to the first hydraulic pump or exclusively to the second hydraulic pump or simultaneously to the first hydraulic pump and the second hydraulic pump,
- wherein the first hydraulic pump has a first efficiency maximum at a first volume flow and a first operating pressure and the second hydraulic pump has a second efficiency maximum at a second volume flow and a second operating pressure, and
- one or more of the first operating pressure is greater than the second operating pressure and the first volume flow is smaller than the second volume flow.