A method of using a chemical analysis slide which includes a slide frame and a sheet-like or film-like chemical analysis element for colorimetric determination of a specific component in an aqueous liquid sample, which method includesapplying an aqueous liquid sample to the chemical analysis element, andcovering the upper face of the side of the slide frame to which the sample is applied with a sheet-like, plate-like or block or brick-like cover to thereby ensure a space between the chemical analysis element and the cover and to prevent evaporation of water or to control evaporation rate of water.