This paper dealt with the seed quality changes of Pinus massoniana treated by different magnetic intensity. The results showed the germination rate of mid-vigorous seeds increased greatly under 0. 2 T and 0.3 T magnetic intensity for l0 rain or 15’rain, especially under 0. 3 T for 15 min, the germination rate was raised from 66% to 83%. To highvigorous seeds with 83% germination rate, the germination rate had any fewer changes after treating with the same intensity of magnetic field. However, seed vigor was still improved. In addition, POD activity increased with treating time under magnetic field intensity above. POD activity of mid-vigorous seeds increased 100% nearly treated for 15 rain under 0.3 T magnetic field intensity, and POD activity of high-vigorous seeds inereased 74% also. On the other hand, SOD activity of mid-vigorous seeds was improved greatly from 0. 20 U/(g ? min) to 0.79 U/(g ? min). In contrast, SOD activity of high-vigorous seeds was cut down.