Nowadays, multi-functional materials are desperately required for adapting the complex environment, which urges us to take more factors into consideration. Here, we proposed a broadband microwave absorber with multi-functionality such as optically transparent, thermal insulating and soundproof properties. Using indium tin oxide (ITO) based metamaterial, the device can achieve above 90% microwave absorption from 5.6 GHz to 23 GHz (cover X and Ku band). Moreover, with designed vacuum structure inside, the device is thermal insulating and soundproof. These multi- functional advantages give the absorber more flexibility in electromagnetic shielding and stealth application, which can be potentially applied in windows related industry.