The invention discloses a synthetic cast iron for hydraulic member production, the mass percentage of the compositions is as follows: 1.8 percent to 3.3 percent of C, 1.8 percent to 2.0 percent of Si, 0.4 percent to 0.7 percent of Mn, 0 percent to 0.3 percent Cr, 0 percent to 0.5 percent of Cu and the rest is Fe. The percentage of the compositions of the charging is as follows: 50 percent to 75 percent of scrap steel, 10 percent to 30 percent of foundry returns, pig iron of 10 percent to 20 percent of pig iron and 1.5 percent to 2.6 percent of recarbonizer. The molten iron is added carbon at low temperature and compensated carbon at high temperature to reach the required ingredients during smelting. The invention can effectively remove the fault of shrinkage porosity inside the high strength gray cast iron; therefore the body strength is greatly improved. The invention has petty microscopic constitution and the casting has compact texture.