Bend Ω shape structure will be made which are connected by three arcs for a complete 180°bend without any straight section because of the needs of the structure for heat exchange tubes in heater.Detailed analysis of the stress and the deformable resilience during tube bending shall be made when the bending mould is designed.Now a simple tube bending way will be adopted based on bending test.A mould of special shape for manual tube bending has been designed which can be used for Ω shape bend with three arcs.The bending radius and the dimension of slot in the bending mould shall first be determined in the design work so as to ensure the quality of bent tube.And designed parameters of the mould have been obtained through the practice.