The invention relates to a method for fine powder desorption and TEAL inactivation of tail gas in a gas-phase polyolefine process. The method comprises the following steps: 1) the tail gas discharged from a product receiving bin enters a first filter to be subjected to primary dry-type filtration; 2) the filtered tail gas enters a tail gas washing tower to be in reverse contact with circulating washing white oil and a TEAL inactivating agent; 3) the tail gas enters an oil-gas separator, and slight white oil and TEAL inactivating agent liquid, contained in the tail gas, are removed; 4) the tail gas enters a second filter to be subjected to secondary filtration. According to the method, the problem that the fine powder and activated catalyst TEAL (triethyl aluminum), contained in the recycled tail gas, have high possibility of blocking or damaging downstream equipment such as a membrane module can be effectively solved, while the fine powder desorption and TEAL inactivation treatment can be realized, the tail gas recycling efficiency is improved, and the production is conducted safely and stably; besides, a drier and a regeneration unit can be saved through the arrangement of a membrane recycling unit, and the equipment cost can be reduced.