Both the heterogeneous interaction of HONO on the ice surface and the heterogeneous reaction of HONO with HBr on the ice surface have been investigated in a flow reactor interfaced with a differentially pumped quadrupole mass spectrometer. The surface uptake amount and initial uptake coefficient of HONO on the ice surface were determined as a function of the ice-film temperature between 173 and 205 K. The reaction probability of HONO over the HBr-treated ice surfaces has been determined as a function of HBr partial pressures at 190K, 200K, and 230K, respectively. The reaction mechanism is proposed and discussed. Kinetic analysis indicates that the heterogeneous reaction of HONO with HBr on ice surfaces follows the Eley-Rideal type.