In this study, a variable optical attenuator for multi-band use based on silica platform is demonstrated. The device is based on the Mach-Zehnder interferometer (MZI) structure with two Bessel curve multi-mode interferometers (MMIs). The variable optical attenuators are prepared to operate in the O+E+S+C+L band (1260?1625 nm) and spectral range of 365 nm. The insertion loss is lower than 10.94 dB with an extinction ratio larger than 8.06 dB. The maximum power consumption of these states is lower than 452.1 mW. At the wavelength of 1310 nm, the rise and fall time of the optical signal are 0.84 ms and 0.88 ms, respectively. Meanwhile, at the wavelength of 1550 nm, the rise and fall time of the optical signal are 0.72 ms and 1.04 ms, respectively. The device has good application prospects in the field of optical communication.