The invention relates to the manufacture of biological samples, particularly to a method for transparently sealing biological microscope slide sample. The method of the invention comprises the steps of dripping 2-3 drops of varnish on a biological sample on a slide, covering a cover glass on the slide in the condition of free from impurities and bubbles after the varnish is naturally paved, slightly pressing the cover glass, putting aside at normal temperature for one week or drying in a drying box at 40 DEG C for 6 hours, adhering a label at one side of the cover glass after the cap sealing agent, namely the varnish is dried and cured, and marking the name of the sample, the material source place of the sample, the manufacturing time, and the name of the manufacturer. The invention uses the varnish to seal the biological microscope slide sample, has high light transmittance, long retention period, low price and high quality, easily obtains materials, does not easily generate bubbles,and is easily dissolved in organic solvents and harmless to tissues. The manufactured sample has good transparency and strong durability, resists to fading, does not degenerate and can be stored for along time, and has the technical effect that the original state of the stored sample is not damaged or destroyed in the process of taking out the sample.