This study was designed and conducted in order to investigate the effect of different levels of urea fertilizer and brown seaweed extract (Nizamuddinia zanardinii) on the physiological traits and grain yield of wheat. Experiment was carried out in the form of factorial in completely randomized design with three replications at five levels of brown seaweed extract (zero, 5, 10, 15 and 20 percent) and three levels zero, 25 and 50 percent of recommended  using rate of 46 percent urea fertilizer (the recommended using rate of urea fertilizer was 300 kilogram per hectare). After the growth and complete ripeness of wheat, the amount of grain soluble carbohydrate, the average weight of spike, the average number grains of spike, grains weight of spike, harvest index of spike, grain yield and biomass were measured. The obtained results showed, using seaweed extract led to a significant increase in the amount of investigated growth indices in comparison to control. In treatments in which the combination of seaweed fertilizer with 25 percent recommended using rate of urea fertilizer was used, the mentioned growth indices significantly increased, which indicated the synergistic and interaction of seaweeds and urea fertilizer. In treatments in which the mixture of seaweed extract has been used along with 50 percent of recommended using rate of urea fertilizer, the investigated growth indices showed significant decrease in comparison to the mixture of seaweed extract treatments along with 25 percent recommended rate of urea fertilizer.