This paper focuses on environmental vibration energy harvesting generator to provide low energy for a micro low-power system. A piezoelectric electromagnetic hybrid broadband power generator was developed based on nonlinear magnetic force tuning. The working principle of the power generator was introduced, and its output power characteristics by the piezoelectric system and electromagnetic system were respectively simulated with the software of ANSYS and Ansoft Maxwell. Then, an experiment system was set up to test the output power characteristics of the power generator with the magnetic force tuning. Experimental results indicate that the peak output open voltage from the power generator is 5.8 V at the resonance frequency of 60 Hz, which is higher than that of the piezoelectric system(5.5 V)and the electromagnetic system (410 mV)independently. When the natural frequency is adjusted with the magnetic force tuning, its resonance frequency band expands from 45 to 76 Hz as the piezoelectric cantilever beam moves from -15 mm to 15 mm in the vertical direction. And the resonance frequency band expands from 51 to 70 Hz similarly as the cantilever beam moves from 0 to 30 mm in the horizontal direction. The experiments show that the simulation analysis results are coincided with that tested results well. It demonstrates that the broadband energy harvesting system can use in low-frequency environment random vibration and can satisfy the demands of low-power of wireless sensor systems.