Abstract: Considering the variety of absorption coefficient along with different altitudes in different climates, this paper gets the absorption coefficient in a certain altitude by interpolation, sets up the model of transient thermal blooming of collimated repetitively pulsed laser from ground to air, and analyzes the transient thermal blooming by four-dimensional computer code. What is more, the paper simulates the model in 5 atmospheric models and simulates thermal blooming of continuous wave numerically. The results are as follows: In the same condition, after the laser transmits 10 km, in the region close to the North Pole, the nearest motion of the peak at the horizontal axis is 0.0569m in winter; the farthest motion of the peak at the horizontal axis is 0.224m in tropic. In the region close to the North Pole, the power in winter is 10.5 times as many as the power in tropic. Thermal blooming in tropic is more serious than that in mid-latitude region; thermal blooming in mid-latitude region is more severe than that in the region close to North Pole in the same season; thermal blooming in summer is more serious than that in winter in the same region; thermal blooming in summer in the region close to North Pole is more severe than that in winter in mid-latitude region.