The present invention relates to a method to control a crusher, a crusher and a control system for the control of a crusher. The crusher (1) comprises a replaceable first crushing member (4) having a first crusher surface and a replaceable second crushing member (5) having a second crusher surface. The cooperation of the crusher surfaces is defined by at least one crusher setting parameter. From measurements of a quality parameter, which relates to the nature of the crushed material, on at least two different occasions during the service life of a set of a replaceable first and second crushing members (4, 5) and on each occasion for at least two different settings of the crusher setting parameter, a control function can be determined that describes a value, of said at least one crusher setting parameter, which on a given occasion gives a crushed material the quality parameter of which is substantially optimal. The control function is utilized for the adjustment of the crusher setting parameter for a subsequent set of replaceable first and second crushing members (4, 5) in such a way that on given occasion for the subsequent set of replaceable crushing members (4, 5), a crushed material is also given the quality parameter of which being substantially optimal. |