This experiment was carried out during two consecutive seasons of 2016/2017 and 2017/2018 in the experimental field of Fac. of Agriculture Moshtoher, Benha university to study the effect of two forces of magnetic field as (300,150 mt),the distance (0,30,60,90) between magnetic field and plants and their combination on the growth (vegetative, flowering, roots),chemical constituents ,oil of Viola odorata L. the treatment of two forces of magnetic field gave significant effect on No. of leaves/plant, leaves area/plant, fresh and dry weight/plant, No. of flower/plant, pedicel length/plant, fresh and dry weight of flower /plant, fresh and dry weight per plant, N, P, K of leaves . The biggest magnetic field (300 Mt) gave the best results. the magnetic field space at zero with plants gave higher significant results in all parameter under this study. The obtained results indicated that the combination between field magnetic at 300 mt with zero instance gave high significant effect for all data recorded.