A
conductivity image reconstructing method for
magneto-thermoacoustic coupled
tomography includes: acquiring a thermoacoustic source distribution of a conductive object by means of
time inversion according to an electromagnetic ultrasonic
signal received, and performing reconstruction according to the thermoacoustic source distribution to obtain a
conductivity distribution of the conductive object. Specially, the method includes: acquiring a thermoacoustic source on a certain level by means of
time inversion, acquiring a thermoacoustic source of the conductive object by means of interpolation, performing calculation by means of Biot-Savart's law according to
excitation current to obtain a spatial component A1 of primary magnetic
vector potential, subjecting the conductive object to spatial
discretization, giving an initial value [Sigma]<0> of
conductivity, according to the theorem of current continuity, solving a spatial component [Phi] <1> of
scalar potential with the initial value [Sigma]<0> and the spatial component A1, substituting the spatial component [Phi]<1> of the
scalar potential to a relation which the thermoacoustic source and conductivity meet so as to obtain updated conductivity [Sigma]<1>, replacing the initial value [Sigma]<0> with the updated conductivity [Sigma]<1>, repeating the process above, and stopping iteration until a relative error of the conductivity meets an equation: Sigma=||([Sigma]1-[Sigma]0) / [Sigma]0||2<=Sigma0.