The first order and second order MEMS-based transmission low-frequency piezoelectric vibration energy harvesters are designed, which transform the vibration energy under a low-frequency environment (less than 200 Hz) into electricity through a piezoelectric effect to solve the problem of vibration energy harvesting. The first-order transmission energy harvester model includes a first-order transmission beam and a piezoelectric cantilever, the second-order transmission energy harvester model incorporates a first-order transmission beam, a second-order transmission beam and a piezoelectric cantilever. The results of mathematical modeling and finite element analysis indicate that the operating frequency of the energy harvester decrease monotonically with the decline of the Young modulus for the first and second order transmission beams and the piezoelectric cantilever; the design of transmission beam effectively reduces the high-order operating frequency of the harvester and broadens the operating bandwidth. As compared with the first-order transmission beam, the second-order transmission beam has acquired two voltage peaks (respectively 3.18 V/g and 1.33 V/g) at ultra-low frequencies (10.98 Hz and 44.52 Hz) with the acceleration of 1g, which further lowers the system operating frequency and widens the effective working bandwidth (less than 50 Hz). Obtained results show the harvesters are suitable for low-frequency vibration energy harvesting.