The growth of sea weeds is greatly affected by the environmental conditions of ambient water. Especially nutrient salts in sea water function as a major factor to the growth of lavers, so that the content of inorganic substances in lavers could he a criterion for quality evaluation of lavers. In this experiment, the relation between the quality and the content of Zinc and Magnesium which are not only physiologically active and closely related with pigments such as chlorophll and phycobilins but also important in quantify is discussed if such a measurement to be an index for quality evaluation. Sixteen samples of layers were collected from three different culture farms, 7 from Jangrim-Busan, 6 from Wando-Jeon Nam, 3 from Hadong-Gyeong Nam, and classified into 3 quality grades to each farm and to whole samples by organoleptic test. Zinc and Magnesium were analyzed by atomic absorption spectrophotometry. For pigment analysis, chlorphyll was extracted with 85 percent acetone, filtered and the absorbance was measured at 660 nm and the residue was further extracted with phosphoric buffer solution to determine the optical density for phycobilins at 560 nm. The result showed that the total content of Zinc and Magnesium varied between the farms, but kept consistent with quality grades from the same farm. The Zinc content was correlated proportion- ally with the content of phycobilins, and Magnesium content in total ash could roughly represent the content of chlorophll except some examples in which the Magnesium content of chlorophyll-ext ractresiduewasexceptionallyhigher. In conclusion the contents of these metals provide an applicable index for quality judgment of lavers.