Metamaterial absorber (MMA) has been widely used in many fields like stealth and electromagnetic shielding. However the optically opaque property of the MMA hinders them from electronic applications in some scenarios demanding large light transmittance and high microwave absorptivity simultaneously. Here we present a novel metamaterial for simultaneously optical transparency and millimeter wave absorption in broadband, keeping excellent absorption performance in a wide angle range from 0° to 60° both for TE and TM waves. The proposed metamaterial absorber is made of ring-shaped elements. By properly tailoring the geometric parameters of the proposed structure and the surface resistance of the indium tin oxide (ITO) film, we can achieve the optimized absorptivity that is greater than 90% from 28.1 to 42.8 GHz and excellent optical transmittance by use of ITO film with moderate surface resistance, implying that the optical properties of the metamaterial are hardly affected by the periodic meta-atoms. In addition, the polymethyl methacrylate (PMMA) as the substrate has higher optical transmittance than traditional silica glass also contributes greatly to enhance the optical transmittance of the proposed structure. Numerical simulations demonstrate the good performance of the proposed metamaterial consistent to the theoretical analysis, thereby opening an avenue for a number of applications such as the electromagnetic shielding, information security and anti-electromagnetic interference (EMI) et al.