The invention discloses a method for gasifying anthracite by a Lurgi gasifier. The method comprises the following steps: (1) introducing superheated vapor into the Lurgi gasifier so as to carry out heating on the anthracite until outlet gas temperature is 100 DEG C or above; (2) introducing air into the Lurgi gasifier so as to ignite the anthracite, and introducing a gas mixture of the air and the superheated vapor for gasifier maintenance after ignition; (3) introducing a gasifying agent prepared from oxygen gas and superheated vapor for gasification so as to enable the volume content of CO2 in outlet gas to 25% to 28% and enable the volume content of O2 in the outlet gas to be not higher than 0.2%; (4) pressurizing the pressure of the Lurgi gasifier to 3.6MPa to 3.8MPa, and controlling the temperature of the gasifying agent and a vapor-oxygen ratio, thereby obtaining crude coal gas. According to the method, the carbon content of slag is lower than 6%, the consumption of anthracite lumps for per ton of ammonia is 1,000kg to 1,050kg, and the obtained crude coal gas is stable in ingredient, is applicable to the anthracite gasified production of coal chemical enterprises for synthesizing ammonia, methanol, coal-based synthetic natural gas and the like, is high in application value and has good economic benefit.