Due to the large power consumption and high cost of the variable o ptical attenuator (VOA) based on inorganic materials,a kind of polymeric Mach-Zehnder interferometer (MZI) VO A with low-power consumption is designed and fabricated in this paper.The structure and the cross secti on size of the waveguide are carefully designed and optimized to maintain the single mode transmission in the waveguide.Thermal fie ld distribution of the heating electrode is also simulated and analyzed.A VOA with low-power consumption and fast response is o btained by using the photolithography and wet-etching fabrication process.At 650nm operating wavelength,the attenua tion of the VOA is 14.6dB and the power consumption is only 12.3mW.The rise and fall times of the device are 240μs a nd 200μs,respectively.The experimental results show that a low-power consumption VOA device operating at visible wavelength ba nd can be designed and fabricated by using the polymer materials and optimizing the structure.