The Muslims of Mecca did not have the right to defend themselves in the age of the Prophet (peace be upon him), and they were in charge of patience or migration, but seven months after the migration, with the revelation of verse 39 of the Hajj surah, the permission of jihad was given. Muslims formed military corps to defend themselves. The Prophet (peace be upon him) in the Medina period signed peace or non-aggression treaties with various tribes, including a non-aggression treaty with the three tribes of the Jews (Bani Qaynuqa, Bani Nadhir and Bani Qurayza). The war of Muslims with the Bani Qurayza tribe is one of the questionful topics of the early history of Islam, with the military and logistical support of the Ahzab army, Bani Qurayza made their enmity public and acted upon it. The Prophet (peace be upon him) after the defeat of the Ahzab army, was appointed to deal with Bani Qurayza. The Muslims besieged them for 25 days, and the affair eventually came to an end with the killing of some of them. The number of the Bani Qurayza's casualties was 400 to 900, based on most historical sources that narrated this story from Ibn-Ishaq. This article was done aiming to make clear the real number of deaths and examined the number of deaths and finally, concludes that the number of deaths is not high and 400 to 900 people is not correct, the death toll Based on some Shi'i sources, is about 10 to 20 of the leaders of the intrigue.