The invention discloses a water absorbent resin suitable for a wood-pulp core and a preparing method thereof. The preparing method includes the following steps that after 
acrylic acid and deionized water are mixed, then a neutral reaction is carried out with a 
sodium hydroxide solution, the reaction is completed, then a 
sodium metasilicate water solution, 
acrylamide, a cross-linking agent and an initiating agent are sequentially added, and a milk-white 
mixed solution is obtained; 
nitrogen is introduced, mixed liquid is subjected to a 
polymerization reaction under 
ultraviolet rays, and transparent 
colloid is obtained; the 
colloid is granulated, dried and smashed, and resin 
powder is obtained; the resin 
powder is taken and evenly stirred with 
sodium metaaluminate, surface treatment liquid isadded for treatment, and the product is obtained. According to the water absorbent resin suitable for the wood-pulp core and the preparing method thereof, nanoscale 
silicon dioxide is generated in the neutral process and evenly dispersed in a 
reaction system and is capable of improving the liquid passing performance and the diffusivity of the water absorbent resin; the water absorbent resin prepared with the method is low in 
residual monomer, small in 
reverse osmosis amount, large in water retaining capacity, high in particle strength after water absorption, loose and particularly suitable for a wood-pulp-core paper diaper.