The invention discloses a method for extracting lithium through a magnetic microporous lithium adsorbent. The method comprises the following steps: immersing the magnetic microporous lithium adsorbentin a lithium-containing solution so that at least part of the lithium ions are adsorbed by the magnetic microporous lithium adsorbent; separating the magnetic microporous lithium adsorbent out of themixed system, and desorbing the lithium ions in the magnetic microporous lithium adsorbent by use of water. According to the method disclosed by the invention, lithium is extracted by the magnetic microporous lithium adsorbent, the preparation method of the magnetic microporous lithium adsorbent is simple and does not need granulation, and can quickly realize solid-liquid separation of the adsorbent and the adsorbate; the adsorbent has the advantages of large adsorption capacity on the lithium ions, high selectivity, simple elution and regeneration and long cycle life; moreover, with good magnetism, the adsorbent maintains the adsorbability and structural integrity of an adsorption material, and has excellent chemical stability. The method can be applied to the separation and extraction of lithium in lithium-containing salt lake raw brine, the salt lake brine after proper concentration and the diluted salt lake old brine so as to prepare lithium carbonate or lithium chloride products.