Fe_41.5Co_41.5Zr₇B₉Cu₁ and Fe_38.5Co_38.5Zr₇B₁₅Cu₁ amorphous alloys were prepared by adding 1at.% Cu based on Fe₄₂Co₄₂Zr₇B₉ with low B content and Fe₃₉Co₃₉Zr₇B₁₅ alloy with high B content. Crystallization curves and structure of crystalline phase of the alloys by synchronous thermal analyzer (STA), X-ray diffraction (XRD) And TEM (TEM). The effects of Cu addition on the thermal stability and crystallization process of Fe₄₂Co₄₂Zr₇B₉ and Fe₃₉Co₃₉Zr₇B₁₅ amorphous alloys were investigated. The results show that the addition of Cu slightly improves the thermal stability of Fe₄₂Co₄₂Zr₇B₉ amorphous alloy, and significantly improves the thermal stability of Fe₃₉Co₃₉Zr₇B₁₅ amorphous alloy. For Fe₄₂Co₄₂Zr₇B₉ and Fe₃₉Co₃₉Zr₇B₁₅ amorphous alloys, there is obvious peak shift(XRD) at the initial stage of crystallization. For Fe_41.5Co_41.5Zr₇B₉Cu₁ and Fe_38.5Co_38.5Zr₇B₁₅Cu₁ alloys, there is almost no peak shift during the crystallization process. TEM results show that the addition of Cu improves the distribution uniformity of nanocrystals and slightly increases the grain size. The effect of Cu addition on the thermal stability and crystallization process of Fe₃₉Co₃₉Zr₇B₁₅ alloy with high B content is greater than that of Fe₄₂Co₄₂Zr₇B₉ alloy with low B content.