The invention provides a symmetric cantilever assembly bridge accurate positioning construction control method. The method comprises the following steps that (1) sleeves or holes are reserved in the reference block segment precast process, reference block precast cantilever assembly segments are mounted through a wet connection method, and wet joint concrete is poured; (2) the sleeves are pre-buried in a structure body in the bent cap pouring process, a suspension system is mounted through screws in the sleeves which are preinstalled in a bent cap in a fastened mode, and adjustable spiral jacks are adopted for supporting the suspension system; (3) the reference block precast segments are hoisted to the ends of suspension beams through suspenders and are fixed to the suspension system; (4) the reference block segments are adjusted to the design position through measurement and check by means of the suspension system, outer pull rods penetrate through the bent cap, and inner bracing devices are mounted between the reference block precast segments and the bent cap; and (5) after fixation is completed, a formwork is mounted, concrete is poured, equal strength stretch-draw is conducted, a rigid framework system is formed, and accurate positioning of reference blocks is achieved.