As important opto-electronical devices, nanofilm photodetectors constructed from inorganic low-dimensional nanostructures have drawn prime attention due to their significance in basic scientific research and potential technological applications. This review highlights a selection of important topics pertinent to inorganic nanofilm photodetectors processed via solution strategies. This article begins with a description of the advantages and drawbacks of nanofilm-based photodetectors versus 1D nanostructure-based ones, and then introduces rational design and controlled syntheses of various nanofilms via different wet-chemical routes, and then mainly focuses on their optoelectronic properties and applications in photodetectors based on the different types of nanofilms. Finally, the general challenges and the potential future directions of this exciting research and technology area are presented.