In order to solve the problem that the frequency and field strength of repetitive transcranial magnetic stimulation (rTMS) devices are difficult to match SPIO nanoparticles for biological experiments or clinical research, this paper proposes a weak magnetic field rTMS pulse generation circuit (WALI-rTMS) whose frequency and field strength can be widely adjusted. Based on the traditional rTMS discharge circuit, this paper presents an inductive connection discharge circuit to solve the problem of high voltage stress of thyristor between DC power supply and charging capacitor; At the same time, the demand gain of rTMS pulse generation circuit is calculated, and the constant voltage closed-loop variable frequency control is realized for WALI-rTMS circuit with the discharge voltage as the control object. Finally, a pulse width 200 μs. The frequency is adjustable at 5–100 Hz and the output field strength is 5–100 mT.