Dendritic Ni2P microstructures were successfully synthesized by a facile hydrothermal route. X-ray powder diffraction, energy dispersive X-ray spectrometer analysis, and Field-emission scanning electron microscopy were used to characterize the as-obtained products. The results showed that the as-prepared product had a hexagonal phase and was composed of a large quantity of well-defined dendrites which have the secondary branch-like structure. Further study shows that the morphology of the as-obtained Ni2P microstructures was highly dependent on the amount of ethylenediamine tetraacetic acid, the reaction temperature, and the reaction time. Then based on some captured intermediates, a possible growth mechanism of the as-obtained Ni2P dendrites was proposed.