A method is established to determine trace selenium in propolis by microwave digestion-molecular fluorescence quenching. After microwave digestion,propolis samples reduces Se( Ⅵ) in digestion solution to Se( Ⅳ) with hydrochloric acid. Then,the propolis samples make chromogenic reaction with iodide and Rhodamine B. When I3-and Luo Danming B form an ion association complex,the fluorescence of Luo Danming B solution is suddenly extinguished. When the selenium concentration is in the linear range of 0 ~ 0. 100 μg/mL,the fluorescence quenching is proportional to the concentration of selenium( IV). The linear regression equation is y = 3 536. 1x + 4. 761 9. The linear correlation coefficient is 0. 9995,and the recovery rate is between 96. 8% to 103%. The relative standard deviation( n = 4) is less than 4. 2%. The limit of detection is 0. 001 0μg/mL. The method has high efficiency,less selenium evaporating,accurate measurement and strong practicability.