©　2016,　Editorial　Department　of　Journal　of　Chang＇an　University　(Natural　Science　Edition).　All　right　reserved.　In　order　to　study　the　effect　of　n-butanol　addition　to　biodiesel　on　engine　performance　and　emissions,　the　physical　and　chemical　properties　of　biodiesel-n-butanol　blends　with　0,　10%,　20%　and　30%　n-butanol　by　mass　fraction　were　evaluated.　Then　the　combustion　and　emission　characteristics　of　the　biodiesel-n-butanol　blends　were　investigated　by　the　engine　dais　experiment.　The　results　show　that　the　density,　viscosity,　surface　tension,　cetane　number　and　lower　heating　value　of　the　biodiesel-n-butanol　blends　decrease　with　the　increase　of　n-butanol　mass　fraction,　and　the　viscosity　of　the　blends　with　30%　n-butanol　can　be　reduced　by　39.3%.　For　the　biodiesel-n-butanol　blends,　the　fuel　injection　delay,　ignition　delay　and　peak　heat　release　rate　increase,　the　maximum　in-cylinder　pressure　and　combustion　temperature　decrease,　the　combustion　duration　shortens　and　the　effective　thermal　efficiency　increases　with　the　increase　of　n-butanol　content　in　the　blends.　Smoke,　CO　and　HC　emissions　of　biodiesel　are　lower,　while　NOx　emissions　are　higher　than　those　of　diesel.　NOx,　smoke　and　CO　emissions　of　the　blends　reduce,　but　HC　emissions　increase　with　the　increase　of　n-butanol　content.　NOx　emissions　of　the　blends　with　10%　n-butanol　are　lower　than　diesel.