The local mechanical properties and the serrated flow behavior of a Cu₃₆Zr₄₈Al₈Ag₈ bulk metallic glass (BMG) have been investigated using nanoindentation. The influence of structural inhomogeneity on the deformation behavior of the BMG is confirmed. The loading rate plays little role in the deviation degree of load-displacement (P-h) curves. It was found that the accumulation of different kinds of serrations leads to the deviation of the P-h curves under a low loading rate. The deviation degree is associated with the numbers and characteristics of the serrated flow. Under a high loading rate, the simultaneous operation of multiple shear bands leads to the disappearance of the serrated flows, and the deviation degree of the P-h curves with each other is assumed to be related to the accumulation of different inconspicuous serrated flows.