This paper describes the catalyst activity of quaternized poly(styrene-g-ethyleneimine) (cross-linked with 3-% divinylbenzene) having linear (nonbranched) polyethylenimine blocks. The reactions employed were substitution reaction (RBr+Y→RY+ Br; Y=CN, CHCO) and dichlorocyclopropanation of cyclohexene with CHCl–NaOH system. The above catalyst which was quaternized with butyl bromide, 1, showed a higher catalyst activity in comparison with similiar cross-linked resins having dimethylbutylbenzyl-ammonium 2 and trimethylbenzylammonium groups 3, respectively. In addition, the catalyst activity of quaternized polyethyleneimine having linear structure, 4, was also examined and compared with that of other quaternary ammonium salts 5—8. © 1979 The Society of Polymer Science, Japan.