The　properties　of　two　types　of　silicon-oxide　alloys,　amorphous　silicon-oxide(a-SiOx)　and　nanocrystalline　silicon　oxide(nc-SiOx)　prepared　by　using　very　high　frequency(VHF)plasma　enhanced　chemical　vapor　deposition　(CVD)system,　and　their　application　in　amorphous　silicon　and　nanocrytalline　silicon(a-Si/nc-Si)　double　junction　solar　cells　were　studied.　The　a-SiOx　and　nc-SiOx　films　were　obtained　by　optimizing　gas　flow　ratio,　RF　power　and　deposition　pressure　as　follows:　1)a-SiOx:B:H　films　with　bandgap　of　2.1　eV,　and　refractive　index　of　3,　which　was　used　as　P1　layer　of　a-Si　top　cell,　and　2)nc-SiOx:P:H　films　with　bandgap　of　2.2-2.5　eV,　refractive　index　of　2.0-2.5,　and　crystallization　fraction　of　25%-40%,　which　was　used　for　both　middle　reflection　layer　of　a-Si/nc-Si　tandem　solar　cell,　and　n2　layer　of　nc-Si　bottom　cells.　Eventually,　the　optimal　SiOx:B:H　and　nc-SiOx:P:H　films　were　used　to　prepare　a-Si/nc-Si　tandem　solar　cells　on　glass　substrate　of　0.79　m2,　with　initial　Pmax　of　101.1　W,　corresponding　to　12.8%　total　area　initial　efficiency,　and　stabilized　Pmax　of　87.3　W,　corresponding　to　11.1%　stable　efficiency.　©　2016,　Editorial　Board　of　Acta　Energiae　Solaris　Sinica.　All　right　reserved.