Abstract: Based on the studies about the problem that a large number ofpeasant workers in China lack the platform for expressing their own interests,the paper indicates that when the institutionalizing organizations fail to provide the platform for expressing peasant workers' interests,they will choose non-institutionalizing organizations,which is harrnful to the expression of their interests and social stability.As an organization for expressing peasant workers' interests,Labour Union has more advantages,so it is an inevitable choice for them.