In the current research an experimental study was done to show the effect of pulse flow on theeffectiveness of shell and tube type heat exchanger. the study was in the case of steady and pulseflows with a changing mass flow rate of hot water flowing inside the pipes of the heat exchanger forthe range between (0.0273-0.0819 kg / s) at fix mass flow rate of cold water that flows through theshell and on the outer surface of the pipes when (0.0416 kg / s), to obtain pulsing a used wassolenoid valve. The research aims to measure the percentage effect of independent factors whichwere presenting the mass flow rate of hot water, flow type and the surrounding environmentconditions of the experimental side upon shell and tube type heat exchanger performance usingexperimental design technique at the significant level (0.05).The results derived from theexperimental tests showed that pulse flow leads to increase internal heat transfer coefficient (hi)comparing with its value in the steady flow and the highest increase was by (9.75%) at a mass flowrate of hot water (0.0416 kg / s) and increases the overall heat transfer coefficient (U), where thehighest percentage was by )4.68%) at a mass flow rate of hot water (0.0416kg/s). The results alsoshowed increasing both the number of transmitted units (NTU) and the effectiveness of the shelland tube type heat exchanger ( ) in the case of pulse flow of its value in the steady flow and thehighest percentage of increase occurring was (4.75%) and (1.85%), respectively, and at the massflow rate of hot water (0.0416 kg / s). Percentage effect of mass flow rate of hot water was (97%,97.42%, 95.5%, 99.48%) and the percentage effect of each flow type and the errors were (2.8%,2.25%, 2.44%, 0.4%) and (0. 2, 0.33%, 2.06%, 0.12) respectively.