Abstract: Based on the results calculated by Zhao Zongci．who used the GCM models from USA to forcast the possible changes of land surface temperature and precipitation in China when doubled CO₂ occurred，the possible climate change during cotton growth period in Hebei Province and its influences on cotton distribution，planting pattern．yield，quanlity，disuse and insect pests were initially predicted under doubled CO₂ condition,The results indicated that under doubled CO₂ condition,the regions suitable for cotton growth would be enlarged，multiple crop index would be increased．yield and quanlity of cotton would be also raised；damage of some cotton disease and insect pests might be heavier，that of others might be lower．