The effect of Ce, Co, and B on the formation of 1:13 phase in La(Fe, Si) 13 alloys was investigated by XRD, SEM and EDS. The results show that Co can improve the formation of 1:13 phase in as-cast LaFe11.6-xCoxSi1.4 alloys, but in as-cast and annealed LaFe11.6Si1.4-xCox alloys, it will hamper the formation of 1:13 phase and help the formation of alpha-Fe(Co, Si) solid solution. Ce2Fe17 phases will form when x reaches a certain value in as-cast and annealed La1-xCexFe11.5Si1.5 alloys. B can improve the formation of 1:13 phase accompanied with Fe2B phase in as-cast LaFe11.6-xBxSi1.4 alloys. B improves the formation of alpha-Fe solid solution in LaFe11.6Si1.4-xBx alloys, and there is almost only alpha-Fe in as-cast and annealed LaFe11.6Si0.9B0.5 alloy. In all, the introduction of Co, B, and Ce cannot eliminate the alpha-Fe phases in corresponding alloys prepared by the high-temperature and short-time annealing process.