The invention discloses a pollution discharge, water and energy saving, recovery and separation device and method of a steam injection boiler and relates to the technical field of boiler equipment. The device comprises a pollution discharge tank, a water blaster, a water-jet pump, a rotary discharging machine and a boiler water filling pool. High-temperature, high-pressure and high-salinity boiler water from a boiler pollution discharge pipe tangentially enters the pollution discharge tank, expands and depressurizes inside the tank, and generates a large amount of steam through flash evaporation; due to the function of the water-jet pump, the water blaster is kept in a negative pressure state from minus 100 kPa to minus 50 kPa; steam generated inside the pollution discharge tank is sucked in through the water blaster and dissolved in cold water from the water-jet pump, heats the cold water and is stored in the boiler water filling pool to be recycled; and the high-salinity water is separated from steam under the effects of flash evaporation and rotation, stored in the bottom of the pollution discharge tank, and discharged out of the tank through the rotary discharging machine, so that crystallized potassium, sodium and other saline materials or alkaline materials are prevented from adhering to the wall of the pollution discharge tank. The pollution discharge, water and energy saving, recovery and separation device can be used in cooperation with the steam injection boiler, and the steam injection boiler can be a fluidized bed boiler, a pulverized coal furnace, a grate furnace, a gas-fired boiler or an oil fired boiler.