I have made an attempt to read the tower imagery in some of Yeats’s middle and last poems. The tower is a key symbol in his poetry. He purchased a Norman tower in 1917 and moved into it to live in summers from 1919. Since then, it had become an emblem of his profound philosophy in his philosophical poetry. I read both the tower poems and their social and historical backgrounds to understand his works more deeply. I also study the way his tower poems reflect Neoplatonic symbolism and intellectual symbolism. The tower symbolizes the poet's spiritual and historical changes in his life; at one time, the tower was a romantic and stable place for the newlywed Yeatses; at others, it served as a retreat at his critical moments and as a place for philosophical contemplation on life and death; eventually it became the poet himself and the eternal symbol of his art as well.