Abstract: Isoseismal lines of 59 earthquakes occurred in middle south segment of Tanlu fault zone are collected. Seismic intensity attenuation parameters in eastern and western part of Tanlu fault are inversed respectively by genetic algorithm. The one norm of misfit function is used and constraint on far field of seismic intensity attenuation curve is added during the inversion. A bootstrap technique is adopted to repeat the inversion process for several times to evaluate the stability of inversion. Results are compared with the fifth generation seismic ground motion parameter zonation map, it shows that seismic intensity attenuation curve can converge even no data are added in near and far filed by proposed inversion method in this paper. Seismic intensity attenuation of eastern and western part of Tanlu fault are different from those of fifth generation seismic ground motion parameter zonation map. Besides, the seismic intensity attenuation of eastern part and western part are different from each other. This difference may be related to the medium velocity structure and attenuation characteristic.