Seaweed is an important and high economy value commodity. There are various methods to increase the quality and productivity. The aim of the study was to improve the quality, quantity and production of seaweed (Gracilaria sp.) by using Kaizen approach. There were intervention ways; those were long line method, grouping method and charcoal pocket application. This study was conducted for 3 months from March 25, 2018 to May 25, 2018 (one cultivation cycle) in Tambaksari village, Karawang, West Java. Some parameters were observed during the study including daily growth rate (weight and length), water quality parameters (pH, temperature, salinity, dissolved oxygen, nitrate, high water), and productivity. The measurement of weight and length of thallus were conducted once a week, while for water quality parameters were once every three days. The long line method in deeper part of pond had higher profit (7.7% or IDR 12,451,200) than that of in shallower part of pond (IDR 11,195,200). Grouping method resulted better quality of harvested seaweed and led to get higher profit (17% or IDR 4,400,665) than that of without intervention (IDR 1,681,165). The charcoal pocket application influenced to the growth rate of non pocket treatment was about 416,46 g/week than that of with pocket (233.11 g/week) and with charcoal pocket treatment (304.33 g/week). So that the most effective method to be applied was the longline method in deep and grouping method gave more quality impact of harvest result.