The invention discloses a bubbling type ultrasonic atomized mercury valence transformation device and a method, and aims to efficiently transform mercury of 
oxidation state, which is in 
coal-fired 
flue gas and can not be measured easily, into mercury of element state, which can be measured easily. The device provided by the invention is characterized in that 
flue gas extracted in the field is treated by a bubbling type reactor, so that a great amount of micron-sized bubbles are generated; meanwhile, an 
ultrasonic atomization technology is used to treat stannous 
chloride hydrochloric acid solution, so that a great amount of micron-sized 
fog drips are formed; after the bubbles and the 
fog drips are combined, the contact area of sample gas and stannous 
chloride hydrochloric acid solution can be improved greatly; and meanwhile, a baffle plate is arranged to prolong the 
interaction time of sample gas and stannous 
chloride hydrochloric acid solution. According to the invention, the efficiency of transforming mercury of 
oxidation state into mercury of element state through a stannous chloride 
wet chemistry method can be improved to the utmost extent, the operation of continuously transforming mercury of 
oxidation state into mercury of reduction state on line under the condition of a laboratory and practical 
flue gas can be realized, and real-time, comprehensive and accurate measurement of mercury state in an on-line mode can be implemented.