A method for forming a complex film having a porous coating is in particular as follows: firstly, holes of a porous substrate are filled with liquid; a raw material is converted into fused or semi-fused liquid drops by using a heat source; then, the liquid drops are coated on the surface of the porous substrate filled with liquid; the liquid in the holes of the porous substrate is gasified by the high temperature of the liquid drops so as to form steam through the liquid drops so that the liquid drops are sprayed into different blocks; irregular and dispergated flat particles are formed after cooling solidification, and stack particles are continuously formed; therefore, a complex film having a porous coating is formed. In addition, the invention further provides a device for forming the complex film having a porous coating.