The invention discloses a preparation method of a high temperature resistant PSA tape for a capacitor. The method includes mixing a styrene-butadiene-styrene triblock copolymer with a reaction solvent with stirring, heating up for dissolution, adding active monomers and initiators in batches under the protection of nitrogen, reacting for a moment and adding tackifying resin and curing agents, reacting for a moment and cooling to obtain the PSA, coating the PSA on a base material, coating a separant on the back side of the base material, and drying to obtain the PSA tape. According to the preparation method, the production cost is reduced, the melting temperature of the PSA is improved to above 170 DEG C from below 100 DEG C when the PSA is unmodified, the obtained high temperature resistant PSA tape has firm adhesion without falling off or displacement, leads have no adhesive residue, the problem that a core is bonded and difficult to pull during a board removal is solved, and production technology requirements for capacitors are satisfied.