Abstract: Cultivars of the abortive-seeded longans, Minjiao 64-2and Baihe, and the large-seeded Jiuyuewu were used for the experimentation.The effects of time, light, and sucrose and boric acid concentrations on the pollen viability were determined by the seed′s in vitro germination, and the stigma receptivity, by the method of benzidine-hydrogen peroxide.The results showed that the pollen viability of the 3cultivars changed with time, and those of Minjiao 64-2and Baihe were lower than that of Jiuyuewu.Light exposure significantly increased the germination rate for Minjiao64-2, but not for Baihe or Jiuyuewu.The suitable sugar content ranged 5%-10%for all three varieties.And, the adequate boric acid content was 50-100mg·L-1 for Minjiao 64-2, 50-200mg·L-1 for Baihe, and 100-200mg·L-1 for Jiuyuewu.The stigmas of the 3cultivars appeared to be receptive from the first to the fifth day after blooming.