A heat dissipating device includes a chamber with an evaporation portion and a condensation portion, the chamber including a refrigerant. The chamber further includes an evaporation portion scraping brush provided corresponding to the evaporation portion, the evaporation portion scraping brush being able to sweep relative to an inner surface of the evaporation portion. A refrigerant liquid film is formed on the inner surface of the evaporation portion. Since the fluid refrigerant is uniformly applied to an inner surface of the evaporation portion to form a liquid film, the heat dissipating ability of the heat pipe heat dissipating device is improved, and the heat dissipating uniformity of the heat pipe heat dissipating device is enhanced. A heat dissipating method is also provided.