This study shows the effect of dynamic flow on the degradation behaviour and mechanical integrity of porous magnesium. A test rig that mimics the environment surrounding a cancellous bone was developed and a dynamic immersion test was performed to assess the degradation rate of the material for bone scaffold application. Three different percentages of porous magnesium (30%, 41%, and 55%) were immersed in simulated body fluid. The results show that mass loss and mechanical integrity of the specimens deteriorated linearly with an increase in porosity and degradation time, correlating to a drop of 41% and 89%, respectively, within 3 days.