This study presents seismic hazard analysis that aims to estimate peak ground acceleration of Semarang for 500 – year return period earthquake that is to validate the Indonesia seismic rules. The seismic hazard analysis is based on geology and history condition by probabilistic seismic hazard analysis (PSHA) method using EZ FRISK program that models fault sources in three dimensional representations. The seismic sources considered are the acknowledged earthquake potential to a depth of 200 km within radius of 500 km from Semarang. This study utilizes a logic tree to cover uncertainties within one method of earthquake assessment. Seismic parameters are calculated by the method of Kijko & Sellevoll and Weichert. Three attenuation models are chosen for determination of the ground motion. The attenuation model of Youngs is selected to represent the subduction environment of Java and attenuation models of Boore et al. and Sadigh et al. are selected to represent shallow crustal fault surrounding Semarang. The result of the analysis shows that the peak base acceleration of Semarang is 0.17 g for 500 – year return period. The value is still on the range of that of Indonesia seismic rule. Keywords: Ground motion, peak base acceleration, probabilistic seismic hazard analysis, three dimensional seismic source.