Automated　fiber　placement(AFP)　has　been　used　to　form　the　large　aircraft　composites　structure　in　recent　years.　To　ensure　the　consistency　of　process　in　AFP,　the　compaction　roller　should　be　flexible　to　adapt　to　the　model　surface　with　big　curvature　and　also　press　the　placing　prepreg　uniformly.　In　this　paper,　thin　film　pressure　sensor　and　ultrasonic　microscope　are　used　to　measure　the　pressure　uniformity　and　void　distribution　of　compaction　rollers　with　different　elasticity　modulus.　Compaction　roller　made　with　high　elasticity　modulus　material　exhibited　good　pressure　uniformity　and　also　reduced　the　void　content.　Compared　with　the　polythene　roller,　the　pressure　uniformity　of　the　silastic　roller　is　improved　by　50%　to　60%,　and　the　void　content　is　decreased　by　92.1%.　Based　on　the　fact　that　the　voids　distributed　mainly　on　both　sides　of　the　prepreg　and　the　pressure　was　much　smaller　on　both　sides　of　the　roller　than　that　in　the　middle　area　of　the　roller,　the　shape　of　two　sides　of　the　compaction　roller　is　optimized.　The　best　dip　angle　of　the　side　plane　calculated　by　ANSYS　Workbench　module　is　20°,　the　pressure　uniformity　is　improved　by　42.9%,　and　the　void　content　is　decreased　by　51.6%　further.