Digital　twin　technology　is　a　fast-growing　research　topic,　but　it　is　still　in　its　infancy.　The　organic　combination　of　urban　digital　twin　and　web-based　visualization　of　Spatio-temporal　big　data　is　one　of　the　important　directions　for　future　smart　city　decision-making,　planning,　and　management.　This　chapter　introduces　the　potential　of　web-based　visualization　technology　for　enhancing　the　visualization　of　massive　Spatio-temporal　data.　The　advantages,　key　technologies,　and　common　tools　of　web-based　visualization,　as　well　as　the　common　form　of　visualization　for　different　data.　This　chapter　also　presents　an　example　of　a　web-based　digital　twin　project　called　3D　UrbanMOB,　including　its　feature,　design　concepts,　and　development　details.　This　field　is　becoming　increasingly　important　as　researchers　become　more　conscious　of　the　necessity　to　use　urban　digital　twins　for　monitoring,　modeling,　and　assessment　of　urban　events　in　the　development　of　next-generation　smart　cities.　©　2023　Elsevier　Inc.　All　rights　reserved.