The invention discloses a steam injection boiler and an anti-explosion method and device thereof. The steam injection boiler comprises a furnace chamber, an ignition part, a gas conveying pipe, a flow meter and a controller. The furnace chamber is used for providing a burning place of combustible gas. The ignition part is used for igniting combustible gas in the furnace chamber. The gas conveying pipe is used for inputting the combustible gas into the furnace chamber. The gas conveying pipe is communicated into the furnace chamber. The flow meter is arranged on the gas conveying pipe. The flow meter is used for measuring gas flow in the gas conveying pipe when the steam injection boiler is not ignited. The controller is connected with the flow meter and can obtain the gas flow in the gas conveying pipe measured by the flow meter. When the gas flow obtained by the controller is not smaller than 50 cubic meters per hour, the control can forbid ignition of the ignition part. According to the steam injection boiler and the anti-explosion method and device thereof, the problem that in the prior art, potential safety hazards generated by combustible gas leakage of a steam injection boiler can be effectively solved.