Similar as its counterpart graphene, one of the main obstacles of applying silicene in the modern electronics is the lack of energy band gap. In this work, we present a systematic study on structural and electronic properties of single and bi-layered silicon films under various in-plane strains using density functional theory. Energy band diagram, electron transmission efficiency, and the I-V curve were calculated. It turns out that bi-layered silicon film (BiSF) exhibits energy band gap as the applied tensile in-plane strain above 10.7%. The energy band gap of the BiSF reaches the maximum of about 168.0 meV as the tensile in-plane strain ~ 14.3%. BiSFs grown on various common semiconductor substrates have been modeled. By choosing proper substrate, the energy band gap of the bi-layered silicon film can be opened. This will open a new opportunity of applying 2D silicon structure in the main stream IC industry.