A method of preparing a polyester/polyolefin hot-melt adhesive for use in a solar cell bus bar is disclosed, in which 2,6-naphthalenedicarboxylic acid and ethylene glycol are first sequentially subjected in a predetermined ratio to esterification and polycondensation in the presence of a certain amount of a titanium-based catalyst to result in a polyethylene naphthalate (PNT) with a weight-average molecular weight of 16,000˜20,000. The PNT is then melt-blended with a low-density polyethylene (LDPE) in the presence of a compatibilizer to produce the hot-melt adhesive that can be shaped into films having a high light transmittance, good mechanical properties, high heat and yellowing resistance and thus particularly suitable for use in solar cell bus bars.