Applying theory of the founders of Marxism on democratic revolution and their conception on the relation between democracy and socialism, Lenin makes the theory more comprehensive and develops it in a further step both theoretically and practically. In the thought of V.I. Lenin, the relation between democracy and socialism is an organic, dialectical relationship that could be called "dialectics of living history". Following his thinking, the struggletfor democracy and socialism, for the construction of socialist democracy and the cause of building of socialism is an unified process so as to bring democratic socialism to a thorough victory.