The　(1-x)SrTiO3-xLaAlO3　(x　=　0.3~0.6)　microwave　dielectric　ceramics　were　prepared　by　two-step　synthesis　method.　The　effects　of　LaAlO3　content　on　the　microstructure,　microwave　dielectric　properties　and　crystal　structure　of　(1-x)SrTiO3-xLaAlO3　ceramics　were　investigated.　The　results　showed　that　the　LaAlO3　powder　prepared　by　co-precipitation　method　refines　the　ceramic　grains,　and　the　sintering　temperature　was　reduced　by　about　100℃　compared　with　the　traditional　solid　phase　method.　In　the　studied　composition　range,　a　single　tetrotetic　solid　solution　was　formed.　With　the　increase　of　x,　the　unit　cell　volume　decreases　and　the　quality　factor　Q×f　increases,　but　the　dielectric　constant　Εr　and　resonant　frequency　temperature　coefficient　τf　both　decrease.　When　x　=　0.4,　0.6SrTiO3-0.4LaAlO3　ceramics　get　the　best　microwave　dielectric　properties　at　1500℃　for　4　h:　Εr　=　42.2,　Q×f　=　25643　GHz,　τf　=　5.5　ppm/℃.　©　VDE　VERLAG　GMBH　∙　Berlin　∙　Offenbach.