The present invention relates to a method for two-step synthesis of a pre-hydrolyzed alkyl polysilicate, wherein a condensation reaction rate is maximized by feeding a silica precursor having a hydration degree of 90-100% and a condensation reaction is terminated by further feeding a silica precursor having a hydration degree of 25-70%, so that the present method can remarkably shorten the time of the condensation reaction compared with an existing one-step synthesis method, can shorten the time of the condensation reaction even without the use of a condensation catalyst, to require neither cost for catalyst purchase nor step for catalyst separation in the process, thereby simplifying the process and reducing the manufacturing costs; can easily control the gelation reaction time and the weight average molecular weight by controlling the feeding amount and feed time of the additionally fed silica precursor; and can synthesize a pre-hydrolyzed alkyl polysilicate with excellent storage stability and processability.