The current study was conducted to determine the ability of the green alga Chlamydonas to accumulate some heavy elements, namely zinc, aluminum and chromium, in its cells after exposing it to these elements for a period of 14 days. Moreover, to observe the changes that appear on the alga as a result of its growth in media containing different concentrations of these heavy elements, which are 10, 15, 20, 25mg.L-1 individually, the scanning electron microscope technology was used. The results showed that the algae has the ability to accumulate these elements, and the chromium element was the most accumulated, followed by the zinc element and finally the aluminum element, as the amount of concentrations reached 0.71, 0.15, and 0.30% of the dry weight for the three elements, respectively. In terms of effect, the chromium element was the most harmful to the shape of the cell and its contents, followed by the aluminum element, while the effect of the zinc element was less severe when added individually.