Nauplii in the Instar I –II stages are probably the form of Artemia most widely used in aquaculture. They are also the easiest and earliest live food obtained from the cysts. In order to optimize utilization of cysts for hatching into nauplii, it is useful to know as much as possible about the hatching characteristics of each batch. and in this regard, the critical factors are: temperature, salinity, and pH. Three-way ANOVA with three factors each with three levels including, water salinity (28, 30 and 33ppt), water temperature (25, 28 and 30°C) and pH (7, 8 and 9) has been analyzed on the hatching efficiency of Artemia urmiana cysts for determining the best points of these physical parameters in laboratory condition. There are significance differences between salinity, water temperature and interaction S* W. T, S*pH and W. T*pH (p<0. 05) but there are not any differences between pH treatment and S*W. T*pH interactions The best points are 30ppt, 28°C and 7 for water salinity, water temperature and pH respectively.