The invention discloses a method for manufacturing ultrafine 
powder from 
polytetrafluoroethylene through 
irradiation cracking. The method is characterized in that 
polytetrafluoroethylene raw materials are dried; the dried 
polytetrafluoroethylene raw materials are subjected to low-temperature 
cold treatment by 
liquid nitrogen; the polytetrafluoroethylene raw materials subjected to the low-
temperature treatment are crushed into 
powder materials with the particle 
diameter being 100-1000mum by a crushing 
machine; the 
powder materials are subjected to sealed 
package under the 
gas protection effect; the packed powder materials are placed into an electronic accelerator 
irradiation system for 
irradiation cracking; and the irradiated powder materials pass through an air flow crushing 
machine to be subjected to air flow crushing and grading, and the ultrafine polytetrafluoroethylene powder with the particle 
diameter reaching 0.2-3mum is obtained. The method has the characteristics that the preparation process is simple, the control is easy, the 
energy consumption is low, the process continuous degree is high, the product performance is stable, the prepared ultrafine polytetrafluoroethylene powder has the characteristics that the dispersibility is good, and the agglomeration cannot easily occur. The prepared ultrafine polytetrafluoroethylene powder can be widely applied to the fields of paint, ink, dray powder lubricating agents and space flight and 
aviation appliances, and the material performance is obviously improved.