The effect of catalyzation conditions on microstructures of copper deposits, electormagnetic interference shielding effectiveness (EMI SE), and physical properties of electroless copper plated polyester fabrics were investigated, in order to develop high quality EMI protective clothing. Optimum molar ration of $PdCl_{2}$/KCl and concentration of mixed catalyst were studied. EMI SE of fabrics higher than 40 dB could be obtained over a wide range of frequency level under optimum conditions. FE_SEM analysis of deposited Cu particles on PET fabric revealed that the size of Cu decreased with increasing molar ratio of $PdCl_{2}$/KCl up to 1/8, and that the particles were more evenly and compactly distributed. The size of Cu particles became bigger and less uniform as the molar ratio exceeded 1/8, resulting in a decrease in EMI SE. Optimum concentration of mixed catalyst is 0.01M $PdCl_{2}$/0.08 M KCl. Furthermore as the catalyzation temperature increased from 25$^{circ}C$ to 40$^{circ}C$, the EMI SE of Cu plated fabrics increased, whereas it dropped to about zero when catalyzation temperature exceeded over 40$^{circ}C$.