The intrinsic magnetic properties of Ce 2 Fe 14-x Co x B (x≤4.76) are studied at 25°C using key alloys annealed at 900°C for 25 days. The saturation magnetization (M s ) and the Curie temperature (T c ) of Ce 2 Fe 14-x Co x B increase with Co content. However, the anisotropy field (H a ) of Ce 2 Fe 14-x Co x B diminishes precipitously with Co content. The process of crystal structure refinement indicates that the saturation magnetization of Ce 2 Fe 14-x Co x B is related to the site occupancy of Co atoms at different Fe atomic sites.Co atoms prefer to occupy 8j2 site, followed by 16k2, 4e and 16k1 sites sequentially.Moreover, Co atoms occupying 8j2 site are more effective leading to an increase in theThe individual effects of Ni or Cu on the intrinsic magnetic properties of Ce 2 Fe 12.98x Co 1.02 Ni x B and Ce 2 Fe 12.98-y Co 1.02 Cu y B are evaluated. The maximum solid solubilities of Ni and Cu in Ce 2 Fe 12.98 Co 1.02 B at 900ºC are found to be 8 at.% and 0.8 at.%, respectively. Ni or Cu enhances T c , but decreases both M s and H a of Ce 2 Fe 12.98 Co 1.02 B. The paper also discussed the combined effects of Ni and Cu on the intrinsic magnetic properties of Ce 2 Fe 12.98 Co 1.02 B. The M s of Ce 2 Fe 12.98-x-y Co 1.02 Ni x Cu y B (0≤x≤0.41, y≈0.119) increases after doping with both Ni and Cu, reaching around 155 emu/g. Meanwhile, the H a and the T c are measured to be near 24 kOe and 280°C, respectively.