PURPOSE: To obtain a polyalkylsilane-modified polyethylene which is useful as a raw material of a polishing agent, a resin processing aid, an adhesive, a textile finishing agent, a paper processing agent, etc., by allowing a polyethylene oxide to react with a polyalkylsilane compound in the presence of a condensing agent.

CONSTITUTION: A polyethylene oxide is allowed to react with a polyalkylsilane compound in the presence of a condensing agent. As for the polyethylene oxide, low-or middle-density ones with chain branches are preferred. Substituted or nonsubstituted heterocyclic compounds containing nitrogen, such as pyridine, pyrrole, picoline, quinoline, etc., are used as the condensing agent. A compound of the following general formula SiXp(CnH2n+1)m (wherein X is at least one of halogen, H, OH, OSO2CF3 and t-C4H9; n is 1W6; m is 2 or 3; p is 1 or 2 and m+p=4) is used as the polyalkylsilane compound.