The species of Grateloupia filicina, Grateloupia divaricata in East Sea were investigated taxonmically in order to clarify taxonomic position. The ecological character, external morphology, anatomy of vegetative structure. Blade length are $15{sim}40;cm$, erect from discoidal holdfast of $3{sim}10;mm$ in diameter. Stipe $1{sim}2.5;cm$ long, narrowly cylindrical below, compressed above Grateloupia filicina. Main axis are long and compressed, $3{sim}7;mm$ broad in broadest part. Colors are scarlet to light red. Blade length are $10{sim}25;cm$, erect from discoidal holdfast of $3{sim}8;cm$ in diameter Grateloupia divaricata. Stipe are single and simple $2{sim}5;mm$ broad. Thallus composed of cortex and medulla in section ; cortex composed of $9{sim}10$ layers of anticlinally arranged cortical cell, divided into outer, middle and inner parts. Partial fragments of nuclear 18S rDNAs from the two species of Grateloupia (Rhodophyta) were amplified using the PCR reaction and sequenced to compare their similarity. The partial sequences showed 98.9% similarity each other. Grateloupia filicina has 371 bp sizes and Grateloupia divaricata has 372 bp size. The G+C contents of Grateloupia filicina is 54.3% and Grateloupia divaricata is 53.64%.