One novel octasubstituted trisalkoxotetradecavanadate cluster, [V14O18(tri)2(Htri)6(HCOO)2]·2H2O [1; H3tri = tris(hydroxymethyl)aminomethane], was revealed by a hydrothermal method. 1 shows a new type of fully reduced trisalkoxotetradecavanadate cluster, incorporating the highest number of H3tri ligands, that is constructed by the interconnection of two rare trisalkoxoheptavanadate units via two O bridges. The magnetic and photocurrent response properties were investigated.