This paper presents a triple-output piezoelectric energy harvesting (PEH) system with parallel synchronized switch harvesting on capacitors (P-SSHC) rectifier based on shared capacitors. By analyzing the principle of the P-SSHC rectifier, this paper supports the rationality of using shared capacitors to construct the multi-voltage conversion ratio (VCR) switch capacitor (SC) DC-DC converters. In addition, the adoption of a parallel structure in the multi-output SC DC-DC converters reduces the cross-regulation. Simulation results show that the proposed system not only has good input power adaptability (1/3X,1X,2X) but can also provide triple voltage (0.5V, 1V, 2V) with less cross-regulation. The maximum output power is 14.4μW when peak-to-peak open circuit voltage is 1.7V.