Porous silicon dioxide films featuring low dielectric constant are of great scientific and commercial interest because of their outstanding potential for application to microelectronic interconnect. However, some reliability problems arise in porous SiO2 films due to their poor mechanical performance. Therefore, it is very important to understand the mechanical and electrical properties of porous SiO2 films. New 2-D models with circle pores and 3-D models with cubic pores are proposed in this work. Simulated results of porous SiO2 structures in the case of periodic and random arrangement, which are implemented through ANSYS, are also provided. Critical parameters such as Young’s modulus E and dielectric constant k of porous films are investigated. Calculation results show that dielectric constant reaches as low as 2.5 when porosity of films is about 40%, while E keeps over 3 GPa if porosity remains in the range from 30% to 40%.