To　the　key　question　for　sol-gel　derived　solar　absorbing　films,　the　transition　metallic　salts　were　filtratied　out　and　the　reduction　condition　was　investigated.　The　results　showed　that　nickel　nitrate　was　reduced　into　elementary　nickel　by　the　sol　formula　without　adding　any　other　reducing　agents.　The　best　absorptance　was　obtained　at　80%　nickel　content　(m(Ni):m(Al)=80:20).　The　sintering　temperature　was　determined　at　600°C.　By　these　conditions,　the　prepared　film　using　0.8　mol/L　sol　has　a　normal　solar　absorbtance　of　0.82.