The invention belongs to the technical field of organic macromolecular synthesis and particularly relates to a preparation method of liquid photoimageable solder resist ink. Firstly, a photoactive substance in plants is grafted with epoxy resin, an ester group is prevented from being introduced into resin, the strength and flexibility of the resin are improved, anthraquinones substances secreted by plants and microbes are used as an initiator and are absorbed into the inside and surface of a filter through microbial action, a gum group can be introduced into the surface of the filter to increase the compatibility with the resin, then carboxymethylcellulose is used as a raw material to prepare n-butyl acetate, the n-butyl acetate is compounded with graphene to decrease the contractility during photosensitive resin curing, and finally the compound is mixed and react with thermosetting resin and the like. The prepared liquid photoimageable solder resist ink is small in curing contraction stress and good in curing membrane toughness, the coefficient of thermal expansion is lower than 230 ppm/DEG C, and the preparation method can be widely applied to printed circuit boards.