The invention relates to a method and a device for synchronously removing sulfur dioxide and nitric oxide by a flue gas biological method. The device is formed by connecting a primary eluting tower, an adjusting tank, a secondary biological vulcanization tower, a biological synchronous desulfurization and denitrification tower, a sedimentation tank and a sulfur separator in series. A flue gas purification treatment technology has low inflowing air requirements, is not afraid of dust and heavy metal and does not need strict pre-treatment. Corresponding microorganisms are added into a biological flora to effectively remove heavy metal. Meanwhile, a synchronous desulfurization and denitrification flora is autotrophic bacteria and has certain removing effect on CO2. An operation condition is moderate and the equipment does not need to be antiseptic. Besides, an external substance such as COD (Chemical Oxygen Demand) organic wastewater, only few microorganism nutrient substances and supplementing alkali for adjusting and controlling a pH (Potential of Hydrogen) value in the eluting tower need to be added; and a temperature needed by a rear-end biological reaction is maintained through heat obtained by front-end heat exchange. In a process, large-sized power consumption equipment is not needed; and the device and the method have the advantages that electric power consumption and water consumption are low compared with a conventional treatment process. Compared with the conventional cost, the cost of the whole process is 1/3 that of the conventional process, and the industrial production can be realized.