The invention relates to an electroslag smelting casting method of fixed blades of a water turbine. Consumable electrodes are prepared by adopting a voltaic arc furnace refining method and the fixed blades are prepared by adopting an electroslag smelting casting process through a mould. The chemical components of the consumable electrodes are controlled as follows: C is 0.14-0.19 percent, Si is less than or equal to 0.6 percent, Mn is 1.5-1.9 percent, P is less than or equal to 0.035 percent, S is less than or equal to 0.035 percent, V is 0.02-0.15 percent, Nb is 0.015-0.06 percent, Ti is 0.15-0.25 percent, Al is more than or equal to 0.015 percent, O is less than or equal to 0.0040 percent, N is less than or equal to 0.0080 percent, H is less than or equal to 0.00035 percent, and the balance is Fe. The electroslag smelting casting system and the electroslag guide are controlled as follows: CaF2 is 60-80 percent, Al2O3 is 40-20 percent, or less MgO and CaO (the total is less than or equal to 20 percent); and the electroslag amount is usually 1.5-5 percent of the weight of a casting. The invention has less amount of oxide and sulfide, small size, even distribution, clean casting base body, high cooling speed, large crystallization temperature gradient at the front of solid and fluid, compact casting texture, high size precision and little distortion, and can greatly improve the product property of the refined casting.