A method, a system and a crushing plant for controlling a crushing process, which crushing plant includes a feeder for feeding material to be crushed to a crusher, a first crusher for crushing the fed material, a second crusher for crushing the crushed material and a conveyor for conveying the crushed material from said first crusher to said second crusher. A crushing plant includes measurement means for measuring the volume flow of the crushed material and control means for controlling the feeding speed of the material to be crushed responsive to change in the volume flow of the crushed material.