The invention discloses an anti-coking boiler. The anti-coking boiler is characterized by comprising a boiler body and a feed fan; the feed fan is fixedly communicated with the boiler body through a flange; a hearth is formed in the middle part of the boiler body; a slag collecting chamber is formed rightly below the hearth; a slag outlet and at least two sets of front boiler holes are formed in the frontal surface of the slag collecting chamber; a boiler door is formed in the slag outlet; at least two sets of back boiler holes are formed in the back surface of the slag collecting chamber; and each set of front boiler holes and each set of back boiler holes are correspondingly provided with hole shielding devices. According to the anti-coking boiler, biomass fuel powder is fed into the hearth of the boiler through the feed fan for suspension burning; in the hearth of the boiler, air is taken into the feed fan, and at the same time, oxygen can be supplied to the boiler through the boiler holes to prevent the generation of coking phenomenon caused by long-time stop in a high-temperature area; and meanwhile, an air blower can occasionally adjust the temperature of the hearth, so that long-time operation is not needed.