The present study was conducted to investigate the effect of different levels of Aphanothece halophytica species of Aphanothecaceae family on the growth process and carcass chemical composition of Artemia urmiana nauplius for 3 weeks. For this purpose, the cysts were hatched identical standard conditions. Then 1200000 Nauplius were used in a completely randomized design with 4 experimental treatments and 3 replications (with 100000 in each replication), including control treatment (1 g yeast per 10,000 Nauplius), and experimental treatments of 100 mL/L microalgae included: treatment 1: ( 22×10⁶ cell/mL microalgae), treatment 2: 16×10⁶ cell/mL microalgae) and treatment 3: (13×10⁶ cell/mL microalgae) in cylindrical-conical (2 liter) plastic containers with a temperature of 28°C and a salinity of 30 g/L. The results at the end of the experiment showed that the highest length was associated in treatments 2 and 3 and the highest weight was related to treatments fed with different microalgae levels. However, there was no significant difference in weight between microalgae-treated treatments (p>0.05). The results showed that at the end of experiment, the highest length in treatments 2 and 3 was observed. The highest weight was shown in treatments fed with different levels of algae. However no significant difference (p>0.05) were observed in among treatments fed with algae (p>0.05). Highest moisture content (91.67±0.54%) and lowest lipid content (3.84±0.04%) in the control treatment, the highest percentage of highest dry matter (11.15±0.15%) and lipid (6.54±0.09%) was observed in treatment 2. The highest percentage of protein was observed in treatment 1 (p>0.05). Overall, the results of this study showed that the use of different levels of A. halophytica microalgae on the length, weight and carcass chemical composition of Artemia naupliis showed a better effect compared to control treatment and the use of treatment 2 is recommended in the diet of A. urmiana nauplius.