In order to reveal the physiological function of calcium in the developing anthers of Anoectochilus roxburghii at different developmental stages, we observed the distribution of calcium in pollinium by electron microscope. The results showed: (1) during sporogenous stage, many calcium precipitations appeared in the vacuoles of anther epidermis and endothecium cells, suggesting calcium were related to vacuolation in the cells. (2) In the early stage of meiosis, many calcium precipitates were accumulated in the nucleus of microspore mother cells. When the microspore mother cell divided, a large number of calcium precipitates appeared between the two sets of chromosomes, indicating that calcium were related to meiosis of microspore mother cell. (3) The surface of plastids was covered with many calcium precipitates indicating that calcium were related to the sugar metabolism of the plastid function in pollen cells. The result indicated that there are still a large number of calcium precipitates on the exine of pollinium surface and in mature pollen cytoplasm, so as to reserve the calcium for pollen germination.