Abstract: An experiment was conducted for indoor intensive culture of Litopenaeus vannamei for a period of 80-100 d for the purpose of studying the effect of water quality regulating and controlling by water recycling-treating system at low frequency combined with in-pond facilities and the nutrient budgets for indoor intensive shrimp aquaculture.The water recycling-treating system consisted of rough filter,ozonator,air-liquid mixer,foam separator,dark sedimentation pond etc.In-pond facilities contained microvesicle aerators and water purifying nets.Two culture ponds termed as pond 7 and pond 8 were set as experimental and control pond respectively.There were no water exchange and medicine use in both ponds during the culture period.Same in-pond facilities were used in both ponds and 30% of the total volume of water from pond 7 was circularly treated with the water recycling-treating system at 60,88 and 94 d during culture 100 d,respectively,while no water recycling-treating system was used in pond 8.The results showed that the system could significantly remove NO₂-N,COD_Mn and TAN in culture wastewater by 53.4%-64.5%,53.4%-94.4%(P<0.01)and 31.6%-40.4%(P<0.05).TAN and NO₂-N in both shrimp culture ponds remained low and in the safe range for shrimp growth during the culture period while culture in pond 8 was terminated on the 80th day because of the outbreak of shrimp disease.The main water quality parameters in pond 7 and pond 8 during the culture period were as follows:DO 5.07-6.70 mg/L and 4.38-6.94 mg/L,TAN 0.248-0.561 mg/L and 0.301-0.794 mg/L,NO₂-N 0.019-0.311 mg/L and 0.012-0.210 mg/L,COD_Mn 10.88-21.22 mg/L and 11.65-23.34 mg/L.The shrimp growth index in pond 7 was better than that in pond 8.The per unit yields in pond 7 and pond 8 were 1.398 kg/m² and 0.803 kg/m² respectively.The results of nutrient budgets in culture ponds showed that the major source of nutrient input was feed which accounted for 93.70% in pond 7 and 92.37% in pond 8 of total nitrogen inputs.98.77% in pond 7 and 99.09% in pond 8 of total phosphorus inputs were from feed.Original culture water and juvenile shrimp provided 6.30% and 7.63% of the total nitrogen input,while 1.23% and 0.91% of the total phosphorus input in corresponding ponds.The major output of nitrogen and phosphorus(56.45% and 53.26% in pond 7,and 59.86% and 55.79% in pond 8)were culture water including effluent.37.07% nitrogen and 21.37% phosphorus of total outputs in pond 7,and 31.94% nitrogen and 13.11% phosphorus in pond 8 were transformed into harvested shrimp finally,so the feed conversion rate for pond 7 was higher.7.00% nitrogen and 25.37% phosphorus of total outputs in pond 7,and 9.34% nitrogen and 31.10% phosphorus in pond 8 were the results of water leakage and adsorption.The experiment results showed that the water recycling-treating system operating at low frequency combined with in-pond facilities could effectively improve the water quality in pond even with no water exchange and medicine usage during culture period,increased feed conversion rate and ensured a good harvest.