The invention discloses a method for detecting magnetism of a stainless steel strip. The method comprises the following steps: step I: preparing a stainless steel strip test sample; step II: preparinga test device comprising a balance, a semi-closed organic glass platform and a permanent magnet; step III: placing the stainless steel strip test sample of the step I onto a weighing platform of thebalance, weighing, and recording the weight data m1; step IV: enabling the semi-closed organic glass platform to cover the balance to form a closed space with the balance, and keeping the semi-closedorganic glass platform not to contact the weighing platform of the balance; enabling the plane of the permanent magnet to be fit to a table-board of the semi-closed organic glass platform, and recording weight data m2; step V: repeating the step III and the step IV, and obtaining three groups of m1 and m2; and calculating a magnetism variation indexes C1, C2 and C3 according to a formula that C isequal to (m1-m2)/m1*100 percent, obtaining an average value CX of the three groups of data, wherein CX is less than 0.2 percent, and determining that the magnetism is qualified. By adopting the method, the magnetism of the stainless steel strip can be actually and effectively detected; and moreover, the device is easy to prepare, the method is convenient, and the result is accurate.