In the problem of nonhomogeneous field magnetic resonance imaging (MRI),echo peaks decay quickly due to traditional design of radio frequency (RF) pulse.In this article,using inverse scattering transform (IST) of the nonlinear dynamics and Shinnar-Le Roux selective excitation pulse design algorithm (SLR Algorithm),we have designed the RF pulse for the nonhomogeneous field MRI.Simulation has been made to test the signal loss induced by the excitation of different types of RF pulses.Simulation results show that the RF pulse sequence optimized by IST and SLR algorithm can improve the signal to noise ratio of MRI considerably