NOVELTY - A copper (Cu) indium (In) gallium (Ga) selenide (Se) (CIGS) thin film solar cell is prepared by coating nano-selenide paint and dry film simultaneously on molybdenum electrode of a rigid substrate, or plating or electro-depositing nano-microlite selenide pre-film; heating; moving the piled substrates from top to bottom or vice versa in parallel; compressing; subjecting to vulcanization treatment; compressing; subjecting to hermetical cooling space; infusing an argon and hydrogen sulfide mixed gas; and transferring cooled substrate to series connection for electrode of the battery assembly.    USE - Method of preparing CIGS thin film solar cell (claimed).    ADVANTAGE - The method is low cost and does not employ vacuum.    DETAILED DESCRIPTION - A CIGS thin film solar cell is prepared by:    (A) coating nano-selenide paint and dry film simultaneously on molybdenum electrode of a rigid substrate, or plating or electro-depositing nano-microlite selenide pre-film;    (B) placing piled rigid substrates in a hermetical space in a vacuum room;    (C) heating at 290 degrees C in the presence of hydrogen;    (D) removing, repeating vacuuming and introducing hydrogen, and introducing injecting argon and hydrogen;    (E) moving the piled substrates from top to bottom or vice versa in parallel;    (F) compressing at 350-580 degrees C and pressure of 20-80 kPa;    (G) increasing temperature to 1100 degrees C to obtain macro-crystal dense CIGS;    (H) subjecting to vulcanization treatment at 520-580 degrees C and pressure of 0.3-25 Pa;    (I) compressing at a pressure of 20-80 kPa;    (J) subjecting to hermetical cooling space;    (K) infusing an argon and hydrogen sulfide mixed gas;    (L) cooling to 110 degrees C; and    (M) transferring cooled substrate to series connection for electrode of the battery assembly through laser processing or machinery lineation, or depositing low resistance transparent conduction zinc oxide/aluminum film process.    The selenide pre-film comprises CuGaSe2+CuSe, Ga2Se3+CuSe; In4Se3 or In2Se3+CuInSe2; CuSe or CuSe+Ga2Se3; or CuSe+CuGaSe2.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic cross-sectional view of a CIGS thin film solar cell. Drawing includes non-English language text.