Lamp dynamic water-proof device and method

The present invention provides a dynamic waterproof method for a light fitting, comprising a shell of the light fitting and an aeration pipe with one end communicated with an inner cavity of the shell of the light fitting and the other end extended to dry place. Because the structure is adopted, when the temperature of the light fitting rises, and the pressure inside the shell of the light fitting increases, air in the shell of the light fitting is discharged through the aeration pipe for decompressing; when the temperature of the light fitting decreases, and the pressure in the shell of the light fitting reduces, air in the dry place enters the inside of the light fitting through the aeration pipe so as to dynamically balance the air pressure inside and outside the shell of the light fitting and eliminate the deformation of the shell of the light fitting suffered by air pressure, thereby preventing the decline of sealing property of the light fitting, and preventing low pressure water sucking inside the ligh