The invention discloses a tower crane foundation formed by using external walls of a basement and support piles of a foundation pit. The tower crane foundation comprises a tower crane foundation raft, wherein one side of the tower crane foundation raft is erected on the external walls of the basement, and external wall embedded bars of the basement are arranged between the tower crane foundation raft and the external walls of the basement; upper parts of the external wall embedded bars of the basement are arched into the tower crane foundation raft, and lower parts of the external wall embedded bars of the basement are embedded into the external walls of the basement; the other side of the tower crane foundation raft is erected on top beams of the support piles at the side slope of the foundation pit through a reinforced concrete wall; the reinforced concrete wall is internally provided with top beam embedded bars; moreover, upper parts of the top beam embedded bars are anchored into the tower crane foundation raft and lower parts of the top beam embedded bars are embedded into the top beams of the supporting piles. The tower crane foundation is used for successfully solving a difficulty that a tower crane cannot be directly arranged in the deep foundation pit of the foundation in a foundation construction stage; and the tower crane foundation is quite applicable to a large project which has higher requirements on side slope load of the foundation pit, is smaller in site and has the supporting piles and the external walls of the basement.