Took　the　auxiliary　fascia　console　lid　of　automotive　interior　trimmings　for　example,　the　preliminary　plastic　was　designed　by　Pro/Engineer,　then　the　Moldflow　analysis　on　the　plastic　was　performed.　Those　irrational　factors　of　both　injection　technical　parameters　and　structure　of　the　plastic,　which　would　occur　in　the　injection　molding　process,　were　modified　after　analyzing　simulation　results.　The　rational　plastic　was　obtained　by　repeating　simulation　and　optimization,　which　indicated　that　the　simulation-based　optimization　could　improve　the　plastic　quality　and　efficiency　of　injection　molding.　Meanwhile,　the　comparisons　of　mode　locking　force　and　molding　time　between　microcellular　foam　and　non-foam　injection　molding　were　also　carried　out,　which　showed　the　significance　of　numerical　value　simulation　in　injection　molding　processes.　©　(2012)　Trans　Tech　Publications,　Switzerland.