We propose a polymeric variable optical attenuator using a modified wide angle X-junction structure. The device's size is only one sixth of that using conventional Y-junction structure. A commercial 3D-Beam Propagation Method simulation software was used to optimize and analyze our design, which was then fabricated using benzocyclobutene polyimide. The experimental results well match with the simulation results. The VOA has an attenuation range larger that 34dB for TE polarization by means of thermo-optic tuning. The measured response time was about 100 micro second, which is fast in compared with other thermo-optic device. The compactness of our device makes it very suitable for high density integrated photonics circuits.