The earthen pond cultivation of Gracilaria fisheri, was mainly taken place in three provinces: Surat Thani, Songkhla and Pattani, in the south of Thailand. The relation between the yield quality and environment was investigated for efficient pond management. The samples including seaweed, water and sediment were collected at four ponds in each province for the analysis. The parameters of light intensity, salinity, pH, water depth and transparency were directly measured at the ponds. Agar yield and contaminants of the seaweed were measured. Pigment constituents and some elements in seaweed, in water and in sediment were determined. A highest yield of the seaweed was more than 58 ton ha-1 year-1 fw. The yield inversely related to salinity, nitrate-nitrogen (r = -0.88 and -0.80 respectively, p< 0.05) and epiphyte(r = -0.75 p< 0.05). The pigments showed positive relation to the clay in water while the agar showed positive relation with Mn in water. For major elements, the concentration of K and Na in seaweed related to nitrate-nitrogen and phosphate-phosphorous in water. The controlling of salinity and adding of fertilizer in water could be improved algal biomass, agar and pigment of G. fisheri.