Ca and Mn co-doped BiFeO₃ ultrafine nanofibres were prepared with the purpose of improving magnetic and photocatalytic performances of the one-dimensional multiferroic material. Impurity phase introduced by both Bi fluctuation and Mn substitution can be suppressed by Ca doping and a space group transition from R3c to C222 can also be triggered by Bi-site doping. With co-substitution of Mn into iron site, the Ca_0.15Bi_0.85Mn_0.05Fe_0.95O₃ nanofibres presented a larger saturation magnetization than the singly Ca doping samples, possibly due to the increased double exchange interation of Fe³⁺-O-Fe²⁺, strengthened by Ca and Mn. Photocatalytic degradation test witnessed a similar drop-and-rise performance with the magnetism.