<p>This study aimed to investigate the use of food contact materials (FCMs) for edible fungi, algae, and their products in China, and to establish the dietary exposure assessment parameters according to the contact area method. A total of 280 samples were purchased from markets and online retailers. The food contact area was calculated through direct measurement or by using 3D area measuring instrument. The contact surface area/volume ratio (S/V) of different FCMs corresponding to various edible fungi, algae, and their products was obtained. The qualitative analysis and confirmation of major material types were conducted via infrared spectroscopy. The main FCMs identified included polyethylene terephthalate, polyamide, polycarbonate, polymethylmethacrylate, polypropylene, aluminum, paper, and glass. The S/V values of different types of foods and FCMs varied significantly. The average S/V of FCMs of dried, canned, preserved, and other processed edible fungi and algae were 166.95 dm²/kg, 4.86 dm²/kg, 36.08 dm²/kg, and 81.70 dm²/kg, respectively. We found that 91.74% of S/V values were higher than or equal to 6 dm²/kg, a parameter utilized by both China and the European Food Safety Authority (EFSA). Therefore, employing the theoretical exposure assessment parameter of 6 dm²/kg may underestimate the exposure risk. Thus the practical parameters acquired in this study could be used in the risk assessment to achieve more scientific and accurate results.</p>