For large diameter long stroke multicylinder hydraulic system, constant pressure variable pump and quantitative pump combination were taken as hydraulic system power to satisfy economical and energysaving features. Differential connection was used when the master cylinder was rised,so installed capacity was reduced. Pilot proportional direction valve was used to control up core mould hydraulic cylinder, down core mould hydraulic cylinder and the main cylinder. The requirements of longstroke hydraulic cylinder fast movement are met,the purposes of accurate positioning of each hydraulic cylinder and preventing mechanical impact are achieved.