The invention belongs to the technical field of new material metal material, and relates to the technical field of electroslag remelting, in particular to a N06625 nickel base alloy electroslag remelting method and an applied slag system. The N06625 nickel base alloy electroslag remelting method comprises the following steps that step 1, raw materials composing the slag system are mixed to make pre-melting slag, and are packaged and stored in vacuum; step 2, all white coping is carried out on a consumable electrode; step 3, the consumable electrode is welded to an auxiliary electrode, and a same steel grade starting plate is welded to an ingot plate; step 4, the well welded electrodes, the ingot plate and a crystallizer are assembled and positioned into an electroslag furnace; step 5, power is on and arc is started, and slag is added to the crystallizer by a slag adding trolley; step 6, slagging is carried out; step 7, state steadying is carried out; step 8, feeding is carried out; andstep 9, feeding is completed, and cooling and demoulding are carried out. The steps are simple, operation is convenient, the cost is low, efficiency is high, environmental pollution is less, yield ishigh and condition of finished products is good.