The calculation for the match of heat exchanger and blower has been done for a 5-kilowatt transverse flow CO2 laser and the problem of parallel connection of blowers is discussed. The result of calculation indicates that the effect of parallel connection of two blowers are better than single blower in order to meet the need of output power. According to the result of calculation, two blowers are used in a 5-kilowatt transverse flow CO2 laser and the output power is satisfying.