Nb 2 O 5 :Tb 3+ nestlike microspheres have been synthesized by a self-assembly of nanosheets using the composite-hydroxide-mediated method. The characterizations of X-ray diffraction, scanning electron microscopy, transmission electron microscopy and high resolution transmission electron microscopy show the Nb 2 O 5 :Tb 3+ crystals have a monoclinic phase, polycrystalline structure, unique nestlike shape, and an average diameter of ∼1μm. Comparing UV–vis spectrum of Nb 2 O 5 :Tb 3+ microspheres with that of Nb 2 O 5 nanoparticles, we have found the red shift of absorption edge of Nb 2 O 5 :Tb 3+ microspheres due to the impurity band formation. The catalytic activity of Nb 2 O 5 :Tb 3+ microspheres has also been compared with that of the Nb 2 O 5 nanoparticles, indicating an excellent catalytic degradation activity of the Nb 2 O 5 :Tb 3+ microspheres to methyl orange owing to its hierarchical structure and effective absorption of light. The effective catalytic degradation activity suggests its possible application in the organic pollutant treatment.