Abstract: The pollen viability of five species of Catalp, (Catalpa bungei, C. fargesiif, duclouxii, C. ovata, C. fargesii aud C. speciosa) were studied by germinative method on agar plate. The result indicated that the optimal pollen germinatiou eavironment was 25℃ and 611. The optimal germinative mediums scheme was 10% sucrose, 0.01% boric acid and 1% agar. At the condition of water planting and the room temperature, the rate of germination of pollen was the highest during the first day to the third day. It decreased significantly from the forth day to the end of a week. The rate of pollen germination was the highest and kept stable highest level in cryopreservation and-70℃. It was higher than tha! in-20℃ and 0℃. It was the lowest at the room temperature. After storage in liquid nitrogen, thawing treatment at varied temperate of 35--38℃ for 5rain could greatly increase the viability of pollen.