A novel combined helical piezoelectric energy harvester is proposed. The bottom of this harvester was a right-angle spiral structure, and the top of this harvester was an arc spiral structure. The arc spiral structure was attached to the mass block of the right-angle spiral structure. Four structures can be obtained by rotating the arc spiral with 90 degrees, and the angles are 0 degrees, 90 degrees, 180 degrees, and 270 degrees, respectively. The design of the right-angle spiral structure could reduce the resonant frequency, and the design of the arc spiral structure could not only reduce the resonant frequency, but also enable the overall structure to perform multi-directional energy harvesting, thereby increasing the output. The thickness of the single cantilever beam structure was 1 mm and the width was 6 mm. According to the calculation and the simulation, when the combined angle of the two structures is 180 degrees, the maximum output voltage is 13 V and the maximum output power is 1.3 mW.