Abstarct: Yellow flour beetle L. (Coleoptera: Tenebrionidea) Tenebrio molitor Although it is an important pest of stored products, mealworm has high amounts of protein and fat, which is used as a food supplement in animal and poultry diets. In this research, the effect of 8 different diets on biological parameters was studied in the laboratory under temperature conditions of 25 ± 1 centigrade, relative humidity of 65 ± 5 Percent, and Light to darkness period of 12:12hour. The results of this research showed that there is a significant difference between different diets in terms of the parameters of larval growth period, larval weight, spawning rate and the length of the larval, pupal, full insect period, the longest growth period is in the wheat bran diet and the highest amount of larval weight in the wheat bran diet and the diet that contains wheat bran, Rolled oats, and soy.The highest amount of spawning is related to the diet of wheat bran, baker's yeast, and pistachio skin. The longest larval period is related to the diet of wheat bran, rolled oats, sugar beet pomace, and the longest pupal period is related to the diet of wheat bran, sugar beet pomace, and potato peel. The longest life span of a complete insect is related to the diet of wheat bran, Rolled oats, soybean. In this research, there was a significant difference between the diets in terms of nutritional indicators in three time periods of 15, 30, and 45 days. In this research found that there is no significant difference between different diets in terms of the parameters of Larval survival percentage, the number of dead larvae and emerged pupae, the efficiency of larval/adult formation, the total number of emerged insects and the sex of the whole insect. The highest growth rate was in the diet with baker's yeast and the highest larval weight was in the diet of wheat bran, Rolled oats, and sugar beet pulp.