The purpose of this study is to find out the relation between the magnitude of load in one hand,and natural frequency, strain pattern and decay rate of dynamic strain due to low frequency vibration along a cantilevered beam, in the other hand. The specimen was made of structural steel which has 16.5" length, 1.5" width, and 0.25" thickness. Two strain gages installed 16" far from its free end were used as sensing devices. The data were recorded using a Sanborn machine as oscillograph. The result shows thal the magnitudes of dynamic strain are cubically related to the magnitudes of load, so that their decay rate are squared functions of the load magnitudes.