Dynamic discrepancies of a trickling reactor was studied. The trickling phase reactor has been widely employed in the area of hydrotreating and/or hydrocracking processes during the last decade. Since the process has not been understood thoroughly, the scale-up process solely depends on matching the residence time of two reactors, pilot and actwal, reactor, based on the plug flow assumption. Therefore the dynamic discrepancies between a pilot unit and a commercial unit has been often reported in the literature. This study pursuits two major catagories namely the process time constant discrepancy and the steady gain discrepancy which have already been reported elsewhere. The first report deals the time constant discrepancy and its analog computer analysis and the second report discribes the steady gain analysis via Digital Computa simulation.