A pressure relief valve and an electrolytic capacitor, including: a valve seat, wherein an exhaust passage is formed, an installation groove arranged on the top which communicates with the passage; a blocking cover, movably arranged on the groove between an open and a closed position for opening and closing the passage, a sealing ring arranged between the bottom of the cover and the groove, wherein at least part of the bottom wall forms a guide surface, which extends from the center of the cover radially outward and upward obliquely to the radial edge. The valve can be suitable for the installation of the capacitor to reduce the internal gas pressure therein, maintain the internal gas pressure within a safe range, and at the same time reduce the bulging of the bottom of the capacitor, so that the core package and the bottom are closely attached to achieve effective heat dissipation.