Volute casing is the major component of CRF pump in united water pump house of nuclear power station, whose shape looks like a hodmadod. It is placed at the top of the water channel in PX pump house, connecting with the recycled water corridor. Taking Ningde Nuclear Power Station for example, the installation technology of volute casing formwork is introduced from the lifting and positioning of pre-cast concrete pieces of volute, grouting in the bottom and seam crossing of volute, the installation and reinforcement of the formwork of water corridor, and the installation of piezometer tubes in the outlet of circulating water and other aspects, for providing references to similar projects.