The present invention relates to a crystal of cephalosporin intermediate 7α-methoxy cephalothin (I) and a method for preparing same. The crystal of 7α-methoxy cephalothin (I) undergoes Cu-Ka radiation and X-ray powder diffraction expressed in terms of angle 2θ; the crystal of 7α-methoxy cephalothin (I) has characteristic absorption peaks at positions of 7.34°±0.20°, 12.71°±0.20°, 14.25°±0.20°, 14.68°±0.20°, 16.52°±0.20°, 17.99°±0.20°, 19.98°±0.20°, and 22.69°±0.20°. The crystal of 7α-methoxy cephalothin provided by the present invention is easy to prepare. Related test data shows that the crystal of 7α-methoxy cephalothin has high purity, low impurity content, and good stability. The preparation cost is low, the preparation method is simple to operate, conditions are mild and easy to control, and crystals of 7α-methoxy cephalothin can be obtained stably. The invention is applicable to industrial production.