Micro-alloying is a useful way to improve the magneto-caloric effect of Gd-based bulk metallic glasses (BMGs). However, the minor addition of other elements usually decreases the Curie temperature of BMGs. In this work, we fabricated Gd55Co25Al(20-x)Zn (x) (x = 2, 5) BMGs and studied their magnetic properties. It was found that a minor addition of Zn not only improved the peak value of the magnetic entropy change but also enhanced the Curie temperature of the fabricated BMG. As a result, the Gd55Co25Al15Zn5 BMG exhibits a rather high adiabatic temperature rise up to 5.1 K at a temperature of around 130 K under a field of 5 T.