An improved seismic vulnerability index methodology is formulated on the basis of eight modeled parameters that are designed according to earthquake-resistant design concept and derived from the empirical vulnerability index that was initiated by the Group of National Defense against earthquake, named as GNDT Level approach. The results indicated that there is a good correlation between the analytical modeling approach and the observed fragility features during in-situ field investigations. To prove that the proposed methodology is accurate and reliable, the verification of the current methodology is performed through the experimental testing related to school building damages during Ranau Earthquake.