Owing to diverse crystal structures and intriguing properties, metal phosphates have attracted much attention in recent studies. In this work, two cadmium phosphates, KCd6P7O24 and KCd3P3O11, were obtained by the high-temperature solution method. In the crystal structure, both the title compounds contain two types of P-O fundamental building units. Thermal and spectral analyses were carried out on the title compounds, indicating that both of them have good thermal stability and short UV cut-off edges. In addition, the relationship between the electronic structures and optical properties was studied by theoretical calculations.