Abstract. We consider the braid groups Bn(X) on finite simplicial complexes X, which are generalizations of those on both manifolds and graphs that have been studied already by many authors. We figure out the relationships between geometric decompositions for X and their effects on braid groups, and provide an algorithmic way to compute the group presentations for Bn(X) with the aid of them.As applications, we give complete criteria for both the surface embeddability and planarity for X, which are the torsion-freeness of the braid group Bn(X) and its abelianization H 1 (Bn(X)), respectively.