A demand for large size and high-performance potassium dideuterium phosphate crystals (DKDP) is increasing with the development of high-power laser system. Compared with the conventional methods, a rapid growth method can shorten the crystal growth period and improve the crystal growth efficiency. However, the properties of the rapidly growing DKDP crystals in pyramidal and prismatic regions are different, leading to the inhomogeneity of the properties in different positions and restricts its application in high-power laser systems. In this paper, potassium dideuterium phosphate crystals with a medium size were grown by a point seed rapid growth method. The feasibility of using rapidly-growth DKDP crystal as electro-optical switch and frequency converter was analyzed by transmittance spectroscopy according to the linear absorption properties. The homogeneity of deuterium content and the crystal quality were analyzed by Raman spectroscopy and rocking curve analysis, respectively. This work can provide a reference for the growth and application of large size potassium dideuterium phosphate crystal.