Based on data of 1:50, 000 aeromagnetic survey performed in 1970s, this paper makes an integrated study and detailed interpretation of some low and gentle second-order anomalies in the background of the negative field, fur thermore, it infers and deals with the properties and values of these low and gentle anomalies, and advances some new ore-prospecting clues.Through the description of some examples, the author tries to tell resear chers that due attention should be paid to aeromagnetic low and gentle se cond-order anomalies.