The invention relates to a pressure-sensitive adhesive and a pressure-sensitive adhesive tape, and a preparation method thereof. The pressure-sensitive adhesive provided by the invention comprises natural rubber, styrene-butadiene rubber, nitrile-butadiene rubber, acrylate rubber, terpene resin, C5 resin, phenol formaldehyde resin and isocyanate. The preparation method comprises the following steps: after mixing and plasticizing the four rubbers, dissolving in an organic solvent, adding the other components, and stirring for 20-30 hours to obtain the pressure-sensitive adhesive; and evenly coating the pressure-sensitive adhesive onto a PET (polyethylene terephthalate) film, and drying at 100 DEG C for 1-5 minutes to obtain the pressure-sensitive adhesive tape. The pressure-sensitive adhesive tape provided by the invention has the advantages of low cost, favorable matte effect, high stripping force, no adhesive residue after stripping, high viscosity and the like, and is applicable to packaging LED (light-emitting diode) digital tubes and dot matrix modules.