The invention discloses a water self-evaporating humidifying flue gas device, a dry type electrostatic dust remover and working method thereof and belongs to the field of flue gas purifying. The water self-evaporating humidifying flue gas device comprises a water self-evaporator and a water supplying device supplying water to the water self-evaporator. The water self-evaporator is composed of a shell, a water inlet pipe and temperature-resistant and corrosion-resistant hydrophilic porous packing. Evaporating holes are uniformly formed in the shell. The water inlet pipe is placed inside the water self-evaporator. Water distributing holes are uniformly formed in the water inlet pipe along the diameter of the pipe. The temperature-resistant and corrosion-resistant hydrophilic porous packing is placed around the water inlet pipe. The water supplying device comprises an upper header and a water make-up pump. The water make-up pump is connected with the upper header. The water self-evaporator is connected with the upper header through the water inlet pipe. The evaporating amount of the evaporator can be automatically controlled by the self-evaporating humidifying flue gas device, and accordingly the purpose of removing particulate matters (PM2.5) efficiently is achieved.