The　structure　stability,　mechanical　properties　and　thermodynamic　behaviors　of　Al4Si6La3　compound　in　a　wide　pressure　range　0-100　GPa　have　been　explored　by　performing　first-principles　calculations　based　on　density　functional　theory.　The　calculated　formation　enthalpy　demonstrates　that　the　Al4Si6La3　compound　at　0　GPa　is　thermodynamically　stable　and　exhibits　unstable　with　the　increasing　of　pressure.　The　single　crystal　and　poly-crystalline　elastic　constants　as　a　function　of　pressure　are　also　calculated　and　discussed.　Al4Si6La3　compound　exhibits　ductile　nature　at　pressure　up　to　100　GPa　by　calculating　Cauchy　pressure,　B/G　ratio　and　Poisson＇s　ratio.　It　is　found　that　the　Debye　temperature　and　minimum　thermal　conductivity　of　Al4Si6La3　compound　can　be　improved　to　some　extent　when　the　pressure　is　increasing.　The　analysis　of　electronic　structures　including　charge　density　difference,　Mulliken　overlap　population　and　density　of　state　reveal　that　Al-Si　and　La-Si　can　form　covalent　bonds　in　Al4Si6La3　compound　whereas　Al-La　form　antibonding　states　at　various　pressures.