A method for preparing particle activated carbon relates to the technical field of the production of activated carbon. The main steps of the invention are that: raw materials are screened by a sieve; the crushed raw materials are put into a drying furnace to be dried; the dried raw materials are sent into an extruder to be extruded and molded; the molded raw materials are sent into a carbonization furnace to be carbonized; particle carbonized material is obtained after being crushed and screened; the particle carbonized material is activated by steam in an activating furnace; the tail gas of the activating furnace drives a waste heat boiler to generate steam; particle activated carbon is obtained after the obtained activated material is crushed and screened; the particle activated carbon is put into a cleaning tank to be boiled and cleaned; the boiled and cleaned particle activated carbon becomes finished particle activated carbon after being naturally sunned or being dried in the drying furnace. Compared with the prior art, the invention dose not add any chemicals and prevents the environment from being polluted; at the same time, the invention makes use of the waste heat of the high temperature tail gas generated during the course of carbonization and activation, thus effectively reducing energy consumption and saving energy.