A preparation method for a PEEK (polyether ether ketone) product, characterized by using Na 2 CO 3 as the only condensing agent and adopting the addition of hydroquinone step by step, and comprising the following steps that: during continuous stirring, the solvent of diphenyl sulfone is quickly added to a reactor and is then heated until dissolved, 4,4'-difluorobenzophenone, hydroquinone and diphenol biphenyl are sequentially added, wherein 4,4'-difluorobenzophenone/(hydroquinone + diphenol biphenyl) = 1:1.1-1.2 (mol ratio), wherein the hydroquinone is added after the 4,4'-difluorobenzophenone is dissolved, and the diphenol biphenyl is added after the hydroquinone is dissolved; pre-dried anhydrous sodium carbonate is crushed and screened and is then quickly added to a reaction system according to the mol ratio of 4,4'-difluorobenzophenone/sodium carbonate of 1:1-3 to be continuously stirred for 30 to 50 minutes under 150 to 160°C until phenol and sodium carbonate in the reaction system react to form sodium salts, the reaction temperature is then increased to 190 to 195°C, the formed sodium salts carry out polymerization reaction with the 4,4'-difluorobenzophenone for 30 to 50 minutes, the temperature of the reaction system is increased to 300 to 320°C within 10 minutes, and therefore the reaction speed is increased and the viscosity is enhanced; when the reaction is carried out for 1 to 1.5 hours and the viscosity of the system has little change, the reaction temperature is increased to 320 to 330°C, hydroquinone is immediately added to the reaction system once again according to the mol ratio of 4,4'-difluorobenzophenone /hydroquinone of 1:0.01 to 0.5, the viscosity of the reaction system is quickly enhanced, the stirring is speeded up at the same time, and the heating is stopped after the reaction is carried out for 1 to 2 hours, so that a viscous polymer solution is obtained; finally, the viscous polymer solution is directly and quickly poured into ice water to cool the product into a bulky solid, and the PEEK product is obtained through crushing, ethanol washing and drying of the bulky solid; wherein the hydroquinone added in step is used as a chain extender; and the mol ratio of hydroquinone to diphenol biphenyl is 80:20 to 20:80. during continuous stirring, the solvent of diphenyl sulfone is quickly added to a reactor and is then heated until dissolved, 4,4'-difluorobenzophenone, hydroquinone and diphenol biphenyl are sequentially added, wherein 4,4'-difluorobenzophenone/(hydroquinone + diphenol biphenyl) = 1:1.1-1.2 (mol ratio), wherein the hydroquinone is added after the 4,4'-difluorobenzophenone is dissolved, and the diphenol biphenyl is added after the hydroquinone is dissolved; pre-dried anhydrous sodium carbonate is crushed and screened and is then quickly added to a reaction system according to the mol ratio of 4,4'-difluorobenzophenone/sodium carbonate of 1:1-3 to be continuously stirred for 30 to 50 minutes under 150 to 160°C until phenol and sodium carbonate in the reaction system react to form sodium salts, the reaction temperature is then increased to 190 to 195°C, the formed sodium salts carry out polymerization reaction with the 4,4'-difluorobenzophenone for 30 to 50 minutes, the temperature of the reaction system is increased to 300 to 320°C within 10 minutes, and therefore the reaction speed is increased and the viscosity is enhanced; when the reaction is carried out for 1 to 1.5 hours and the viscosity of the system has little change, the reaction temperature is increased to 320 to 330°C, hydroquinone is immediately added to the reaction system once again according to the mol ratio of 4,4'-difluorobenzophenone /hydroquinone of 1:0.01 to 0.5, the viscosity of the reaction system is quickly enhanced, the stirring is speeded up at the same time, and the heating is stopped after the reaction is carried out for 1 to 2 hours, so that a viscous polymer solution is obtained; finally, the viscous polymer solution is directly and quickly poured into ice water to cool the product into a bulky solid, and the PEEK product is obtained through crushing, ethanol washing and drying of the bulky solid; wherein the hydroquinone added in step is used as a chain extender; and the mol ratio of hydroquinone to diphenol biphenyl is 80:20 to 20:80.