Crystallization control of the hard polyester segments is an important way to design the final properties of a thermoplastic polyester elastomer (TPEE). In this work, the crystallization behavior of TPEE with nanosilica as the nucleating agent was studied. Three kinds of nanosllica with various sizes and surface treatments were chosen for nucleation design. The results reveal that all types of nanosilicas have evident nucleating effects, leading to a remarkable increase of the crystallization temperature of TPEE even by about 30 degrees C. However, the overall crystallization process is highly dependent on the particle size and surface treatment of silica because it is closely related to the nucleation ability of the particles and alteration of the system viscosities. The crystallization temperature of TPEE is more sensitive to the surface treatment of silica, while its crystallization rate shows a higher dependence on the particle size of silica. This work provides a facile way to well tailor crystallization of TPEE.