A survey on the status of giant freshwater prawn (Macrobranchium rosenbergi de Man, 1879) cultured in the low water pH rice fields was conducted on 30 households and a trial on prawn culture was carried out with three different water pH levels (5.5; 6.5 and 7.5) in Hong Dan district, Bac Lieu province from May 2013 to December 2013. The trial of prawn culture at low water pH (5.5 - 7.5) in rice field was designed into 9 plots, with the same characteristics of soil and water quality. The area of each plot was 30 m² (6 x 5m). The stocking densities was 3 PL₁₅/m². In order to control  water pH in rice plots, lime (CaCO₃) was used. The result of the survey showed that the culture techniques utilizing by farmers were simple. the feed was mainly utilized from available resources at the local areas. The survival rate and yield of prawns were 20.1 ± 7.0% and 84.4± 43.7 kg/ha/crop, resepectively. The cost benefit ratio was 205 ± 161%. During 6 months of culture, water temperature, salinity, DO, N-NH₄ were in suitable ranges for prawn growth. The daily weight gain of prawns in treatment I, II and III were 0.13 ± 0.02 g/day, 0.21 ± 0.01 g/day and 0.23 ± 0.03 g/day, respectively. The survival rate and yield of prawns in treatment I, II and III were 16.3% and  9.31 ± 0.37 kg/1,000 m²; 21% and 21.7 ± 4.9 kg/1,000m²; 22.3% and 25.4 ± 0.4 kg/1,000 m², respectively. The profit ratio of three treatments was 31.79 ± 6.12%, 201.5 ± 69.65%, 252.3 ± 4.8%. The survival rate, yield and cost benefit ratio in treatment II and III were not significantly different, but they were significant difference with treatment I (p < 0.05). The integrated freshwater prawn – rice field culture at water pH from 6.5 obtained high efficiency for farmers and its could be practically applied on farms to improve their income in Hong Dan district, Bac Lieu province.