magnetotelluric section groups in this area，starting from the magnetotelluric sounding method and based on previous work． The authors then discuss the sorted profiles one by one，and further explain the basement characteristics

of the Songliao Basin and Dasanjiang Basin Group through grid diagrams，and finally give the following conclusions:

①The Songliao Basin is controlled by the fault and presents high-low-high electrical distribution in the east-west direction．The resistance in the south is higher than that in the north as a whole． ② The resistance values of the Jiamusi block and the Khanka block are small，and their lithospheric structures are stable． The upper-lower and northsouth resistance values of the Wandashan block have large differences，and the structural stability is relatively poor．The more to the northeast among the several blocks，the larger the low resistance range is，which further confirms the unity of the Dasanjiang Basin to a certain extent．