This article attempts to explain Taiwan's civil service reform through the viewpoint of Historical Institutionalism, primarily focusing upon both side of ”Critical Juncture” and ”Temporal Sequence” approach, to articulate the correlations between democratic and bureaucratic system. Three different levels of analysis will be introduced, i.e. from macro to micro, from global, domestic, to individual, to explain how the external factors and driving forces will influence the civil service reform in Taiwan.