The invention relates to a prestressed assembly box-shaped precast concrete tower crane foundation which is formed into a whole by stretching and assembling nine box-shaped precast concrete members which are divided into three types of type I, type II and type III and have open tops by adopting prestressed tendons. The plane of the foundation is a regular octagon, and the resistance to capsizing is isotropic; each box-shaped member has light self weight and can be transported and installed conveniently; sand, stone, soil or other dispersive materials are filled in a box body to be used as the balance weight of the foundation, the cost is low, and the balance weight is reliable; and a sand removing hole is formed at the outer side of each box-shaped member, thereby being convenient for filling and removing the balance weight. Three types of box-shaped members can reliably transfer shearing force by mutual occlusion of outside anti-shearing keys and anti-shearing grooves; prestressed ducts are reserved in the box-shaped members, and prestressed tendons are penetrated into the ducts and then stretched, assembled and formed; and the foundation has good integrity and large rigidity and overcomes the defects of the traditional assembled tower crane.