The invention discloses novel 
functionalized polystyrene resin. The novel 
functionalized polystyrene resin is prepared by performing a 
condensation reaction on 
aldehyde-based 
polystyrene resin and a primary amino-containing functionalization 
reagent, wherein a -CH=N- linking arm structure is formed between the 
aldehyde-based 
polystyrene resin and the primary amino-containing functionalization 
reagent, and a coplanar 
rigid structure is formed by the -CH=N- linking arm structure and a 
benzene ring in the 
polystyrene resin through conjugation. A preparation method of the novel 
functionalized polystyrene resin comprises the following steps: step 1, adding the dried 
aldehyde-based polystyrene resin (PSD) into an 
organic solvent, and performing swelling at 
room temperature; step 2, adding the primary amino-containing functionalization 
reagent H2N-Fg, performing uniform mixing, and performing a reaction for a period of time; and step 3, cooling the mixture obtained after the reaction in the step 2 is performed, performing 
filtration, washing the obtained 
solid, and performing 
drying. The functionalized polystyrene resin provided by the invention can also be prepared from the PSD and the H2N-Fg under 
solvent-free conditions. According to the novel functionalized polystyrene resin and the preparation method thereof provided by the invention, the preparation process is simple, and the functional group content per unit weight of the resin material is high.