Different studies on Litopenaeus vannamei (Boone, 1931) has performed in Iran, but less noted in water quality conditions. Water quality, in addition to creating optimal environment for the growth of vannamei shrimp, as well as cause the live food production and improve economic performance are produced. This study was conducted to evaluate the water quality environment vannamei shrimp in the south of Caspian Sea (Mazandaran province) and in the Caspian Ecology Reaserch Center. The results showed that the enrichment of water out of the ponds, can provide favorable conditions for water quality in the culture of vannamei shrimp with different densities.As a result, Mazandaran province environmental conditions (particularly temperature and salinity of the Caspian Sea) has perfectly suited for optimal growth vannamei shrimp. Therefore, vannamei shrimp (PL12) achieved a final individual weight of 21.1gr in a period culture of 85-day with a density of 35 ind/m2. Also, The nutrients and water quality parameters (Temperature: 27.4±1.79 ° C, Transparency: 10.7±1.2 cm, Salinity: 10.57±0.78 psu, pH: 8.42±0.38, Dissolved Oxygen 8.04±1.35 mg per liter) were within normal limits during the cultuer peirod. Iranian Fisheries Science Research Institute Published