Obstacle-avoiding　Steiner　minimal　tree　(OASMT)　construction　has　become　a　focus　problem　in　the　physical　design　of　modern　very　large-scale　integration　(VLSI)　chips.　In　this　article,　an　effective　algorithm　is　presented　to　construct　an　OASMT　based　on　X-architecturex　for　a　given　set　of　pins　and　obstacles.　First,　a　kind　of　special　particle　swarm　optimization　(PSO)　algorithm　is　proposed　that　successfully　combines　the　classic　genetic　algorithm　(GA),　and　greatly　improves　its　own　search　capability.　Second,　a　pretreatment　strategy　is　put　forward　to　deal　with　obstacles　and　pins,　which　can　provide　a　fast　information　inquiry　for　the　whole　algorithm　by　generating　a　precomputed　lookup　table.　Third,　we　present　an　efficient　adjustment　method,　which　enables　particles　to　avoid　all　the　obstacles　by　introducing　some　corner　points　of　obstacles.　Finally,　an　excellent　refinement　method　is　discussed　to　further　enhance　the　quality　of　the　final　routing　tree,　which　can　improve　the　quality　of　the　solution　by　7.93%　on　average.　To　our　best　knowledge,　this　is　the　first　time　to　specially　solve　the　single-layer　obstacle-avoiding　problem　in　X-architecture.　Experimental　results　show　that　the　proposed　algorithm　can　further　shorten　wirelength　in　the　presence　of　obstacles.　And　it　achieves　the　best　solution　quality　in　a　reasonable　runtime　among　the　existing　algorithms.