In this research 50 fingerling sturgeon fish (Acipenser persicus) with an average weight of 3 to 5 grams were examined. Based on O.E.C.D for 14 days at concentrations of 25, 50 and 75 percent of the LC50 96h diazinon (which is equal to 38/4 ppm) for resident groups. Randomly sampled from each treatment were then transported to the laboratory. For bleeding (in calm conditions without causing any stress), using 2 ml syringes taken from tail vein blood was shed in a container containing heparin anticoagulant. Hematological parameters using standard methods of measuring were studied. The results show that the average number of red blood cells in the control sample 104 × 71 and treated1, 104 × 65 and treated 2, 104 × 63 and treated 3, 104 × 62 level of hematocrit in control samples (23%) and treatment 1, 21% and 2, 20% and treatment group 3, 19% have been and the relationship between hematological parameters showed statistically significant analysis (P≤0/01). There is a relationship between hematocrit and RBC count and MCV. This means that the same number of red blood cells in two different situations but there is no similarity in mean cell volume because they have different hematocrit or by increasing the number of red blood cells from the hematocrit value becomes less than the mean cell volume decreased too. Average mean cell volume in cubic microns, 317 microns minimum of 3 and a maximum of 358 microns per cubic treated in the control group .The amount of hemoglobin in Sturgeon, like all other beings is directly related to the number of red blood cells so that the increase in the number of red blood cells and hemoglobin rises and vice versa. Muscle and gill tissue samples in each treatment, Bowen solution stabilized and sections 7 microns thick sections and tissue samples using H & E stained and studied by light microscope. Histopathological effects of diazinon on muscle tissue degeneration, edema, vacuolization, necrosis, and atrophy of muscle fibers in treatments. Also congestion, stick blade gill, necrotic cells and Shuffle chloride blade gill structure of the most significant changes were observed in fish by diazinon. The histopathological changes were significantly increased with increasing concentrations of the toxin and mortality increased with increasing concentrations of the toxin.