This research mainly focuses on the electromagnetic shielding effectiveness of bamboo -charcoal, using cement mortar with bamboo-charcoal ingredient replacing parts of thin aggregates weight, and then finds the feasibility of electromagnetic shielding effectiveness by using bamboo-charcoal applied to cement mortar. Experiment contains two parts, one is to use different proportions of bamboo-charcoal with replacing with thin aggregates weights( 0%¡B3%¡B5% and 7% ),and the other is to use three kinds of thickness(3mm¡B4mm and 5mm), to measure the effectiveness of electrom- agnetic shielding, and to probe into whether cement mortar with bamboo-charcoal ingredient can shield electromagnetic or not. After researching on cement mortar with bamboo-charcoal, it can be used in civil engineering and ocean engineering, and this experiment will act on the premise which is not affecting the property of cement mortar with bamboo-charcoal, continuing using the condition of reference(Yu,2007) to probe into the electromagnetic shielding effectiveness of cement mortar with bamboo-charcoal, expecting this material can be used to domestic architecture, for protecting the health of our home environment.