Abstract: The heat sum for male catkins ripening of Pinus tabulaeformis Carr., and the daily and hourly changes of pollen density during pollen shedding period in consideration of climite factors were studied in the seed orchard for three successive years (1984—1986). More attention was paid to transporation and dispersal features of pollen inside and outside the seed orchard in the mountainous area. Some ideas of establishment and management of seed orchards have been put forward on the basis of the observation.