We investigate aromatic polyureas which can be fabricated in the form of thin films through CVD. It was found that the polymer possesses a flat dielectric response (k∼ 4.2 and loss <1%)) to more than 200°C The frequency-independent dielectric properties in the investigated frequency range(1kHz∼1MHz), low conductance, low dissipation factor (∼0.005), high breakdown strength (>800MV/m), high energy density (>12J/cm3) and high efficiency suggest this polymer can be a good candidate material for high temperature energy storage capacitors. Breakdown strength was analyzed with Weibull model over a broad temperature range (25°C ∼180°C). Experimental results indicate that aromatic polyurea is more like a nonpolar linear dielectric material because of its highly cross-linked structures. The experiment results further show that this polymer maintains its high performance even at high temperatures.