This study aimed to accelerate the growth and increase the productivity of soybean plants by providing treatment using a magnetic field at the time of seed germination. The research sample was soybean seeds of the Grobogan variety obtained from Center for Research on Various Tubers and Nuts. The magnetic field used in the treatment is in the direction of the magnetic flux density, which changes with time, and the change frequency is 100 times per second. The treatments were given with magnetic flux density from 0.0 mT to 0.5 mT for 20 minutes per day and repeated for five days. Treatment with a 0.1 mT magnetic field resulted in optimum values of germination emergence time, stem growth, chlorophyll content, early flowering time, weight per 10 seeds, and productivity. Treatment with a 0.5 mT magnetic flux density had a negative or no effect on the growth and productivity of soybean plants. Treatment using a magnetic field of 0.1-0.4 mT positively affected soybean growth and productivity, while 0.5 mT did not affect or negatively affect. The treatment of the magnetic field can have positive and negative effects depending on the magnetic flux density used.