An experimental study of co-culture of sea cucumber Holothuria leucospilota with the Pacific white shrimp Litopenaeus vannamei was carried out in the laboratory. Results indicated that nutrient structure of the culture system was influenced significantly by the sea cucumber: the phosphate and nitrate concentrations were enhanced more obviously in the co-culture system than the monoculture system, and by contrast, the ammonium concentration was kept low in the co-culture system. The organic and sulfide contents of the sediment were reduced in the co-culture system, the sulfide content in the co-culture system was (7.71±1.33) mg/kg, accounting for only about one-third of the value of the monoculture system. Co-culture of sea cucumbers had positive effect on the growth and survival of shrimps, the specific growth rate of the shrimps in the co-culture system was (0.69±0.13) %/d, which was significantly higher than that of the monoculture system[(0.45±0.06) %/d]; the survival rate of the shrimps in the co-culture system was 72.5%±22.9%, which was significantly higher than that of the monoculture system 55.0%±17.5%. In the co-culture system, the shrimps had no negative effect on the sea cucumbers, and the sea cucumbers could ingest and assimilate the sediment in the culture system efficiently (with an assimilation efficiency of 36.36%±13.79% for organic matter in ingested sediment). Co-culture of sea cucumber H. leucospilota in the shrimp culture system has both environmental and economic benefits. This co-culture method could contribute to the sustainable development of aquaculture in China.