In this pupper, we consider control oj'a stirred-tunk chemical reactor system with a transportation Ia.4 using a parameter plutw method. Due to wide acceptunce ofproportionulplus-intey~ul-plus-deritlatior (PJD) control in the chemical process industries, a PJD controller is used,for this chemical reactor system. Based on two stability equations and using the PJD guins as the uajustable parameters, the stability boundary and bounduries with a spec$ed gain margin (G.M.), phuse mur~yitr (P.M.), dumpin~y ratio and damping factor are shown in the,first yuudrunt of parameter plunes. The set of ull possible gains to maintain the chemical reactor system's stability, und at the same time, to make the system haring (I prespec$ed umount of G. M., P.M., dumpin~g ratio and dumping ,jitctor is ,fbund. The performance for some representutice PID ,yains chosen in the parameter planes ure checked by, their NJquist plots and Bode dia~grams. The udcuntu~ye of using this approach is that the effects ofparameters on the stability and perfformutw of the control swtem can be easily seen in the parumeter spuce, urzd this can help control engineers to ease the design work by properly udjustin,y the pnrumeters to obtuin the desired system performance.