When the building is on fire,there is a certain requirement to evacutate people safely.In fact the requirement is normally executed by certain standard. Nowadays, both internal and external experts have proposed many ways to change current dealing models to functional standard models.But there need to be further research for functional design of distance on safe evacutation.Based on the dissection of current existed inadequacy,this thesis covers a higher standard of safe distance.That is,if the fire brokes out inside of the building,people should estimate the safe distance according to smoke and heat of the fire,the influnence of the circumstances to time and speed on evacutation.The paper connects engineering theroy of safty of fire disaster and then it designs a model to evacutate people safely.The model will play a part in promoting designing a more functional antifire structure.