NOVELTY - Fabricating a copper/indium/gallium/selenium solar cell by a wet process under non-vacuum condition, comprises: performing a first transparent conduction oxide (TCO) layer forming process (S10) for a substrate having a backside electrode layer by using a first TCO layer forming apparatus; performing copper/indium/gallium/selenium layer and a cadmium sulfide layer forming process (S20); performing a zinc oxide layer forming process (S30) by using a zinc oxide layer forming apparatus; and performing a second TCO layer forming process (S40) by using a second TCO layer forming apparatus.    USE - The method is useful for fabricating copper/indium/gallium/selenium solar cell.    ADVANTAGE - The process is: an integrated process and provides the copper/indium/gallium/selenium solar cell having high conversion efficiency, high quality and high reliability, in an economical and simple manner; and suitable for mass production.    DETAILED DESCRIPTION - Fabricating a copper/indium/gallium/selenium solar cell by a wet process under non-vacuum condition that forms the solar cell having a first transparent conduction oxide (TCO) layer, a copper/indium/gallium/selenium layer and a cadmium sulfide layer, a zinc oxide layer and a second TCO layer, comprises: performing a first TCO layer forming process (S10) for a substrate having a backside electrode layer on it by using a first TCO layer forming apparatus, where the backside electrode layer locates on the substrate with many rollers under it, and the substrate is drove forward, and the first TCO process comprises mixing, a coating layer forming process, drying, compacting, a thermal process, and a cutting process to form the first TCO layer on the backside electrode; performing a copper/indium/gallium/selenium layer and a cadmium sulfide layer forming process (S20) by using a copper/ indium/gallium/selenium layer and a cadmium sulfide layer forming apparatus, where the process comprises mixing, a coating layer forming process, a drying process, a compacting process, a primary selenization/sulfidation reaction process, a thermal process, an impure phase removing process, a rear stage selenization/sulfidation reaction process and a cadmium sulfide layer growing process to sequentially form the copper/indium/gallium/selenium layer and cadmium sulfide layer on the first TCO layer; performing a zinc oxide layer forming process (S30) by using a zinc oxide layer forming apparatus, where the process comprises mixing, a coating layer forming process, drying, a compacting process, a thermal process and a cutting process to form the zinc oxide layer on the cadmium sulfide layer; and performing a second TCO forming process (S40) by using a second TCO layer forming apparatus, where the process comprises mixing, a coating layer forming process, drying, a compacting process, a thermal process, and a cutting process to form the second TCO layer on the zinc oxide layer.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic illustration of the method for fabricating a copper/indium/gallium/selenium solar cell by wet process under non-vacuum condition.    First transparent conduction oxide (TCO) layer forming process (S10)    Copper/indium/gallium/selenium layer cadmium sulfide layer forming process (S20)    Zinc oxide layer forming process (S30)    Second TCO forming process (S40)