The invention discloses a preparation process of multifunctional calcium supplement granules. The preparation method comprises the following steps: 1) removal of oysters; 2) clearing away of dirt; 3)drying; 4) pulverizing; 5) pulping; 6) powder taking; 7) feeding and mixing; 8) drying and pulverizing; 9) preparation of the granules. The calcium supplement granules prepared by the preparation process have good calcium supplementing effect; by taking the oysters as a main raw material and adding sugar, deionized water, edible alcohol and lemon C for mixing and micro-capsulation to prepare the easily absorbed calcium supplement granules, the absorption and utilization rate of calcium is increased favorably, so that calcium is supplemented, and an effect of supplementing trace elements. By the ultrasonic treatment and the assistance in nitrogen bubbling, the dirt clearing effect is enhanced favorably. By adding a food colorant, various prepared colored granules can be applied to water drinking and material mixing, and diversified multifunctional calcium in various colors can be prepared; the preparation process has wide market prospect.