The　band　structure,　density　of　states,　optical　properties,　effective　masses　and　loss　function　of　AlxGa1-xAs　and　InyGa1-yAs　were　performed　by　the　first-principles　method　within　the　local　density　approximation.　The　calculated　direct　band　gap　of　the　AlAs,　Al0.5Ga0.5As,　GaAs,　In0.5Ga0.5As　and　InAs　were　1.608　eV,　1.34eV,　1.02eV,　0.646eV　and　0.316eV　at　G　point,　which　were　direct　bandgap　semiconductor　materials.　In　addition,　dielectric　functions,　the　absorption　function,　refractive　index,　loss　function　and　effective　mass　were　analyzed　in　detail.　The　effective　masses　of　AlxGa1-xAs　and　InyGa1-yAs　were　small,　so　they　have　high　carrier　mobility.　These　results　make　them　to　be　promising　candidates　for　future　electronics.