Abstract: According to the WBR theory and by means of the "Promoted matrix computation method", the authors computed and studied the relaxation equations of strong coupling system, especially the effect of J coupling on transverse relaxation, longitudinal relaxation and cross relaxation. Finally the authors gained the following valuable conclusions. (1) The effect of weak coupling on the computation of relaxation is very small and neglectable. (2) The strong coupling has hardly any effect on the computation of transverse relaxation. (3) The strong coupling has a certain extern effect on the computation of longitudinal relaxation and cross relaxation, especially this effect achieves maximum when the match condition ω_a-ω_b≈2πJ comes into existence and can't be neglected.

Key words: NMR, Relaxation, J coupling, Solomon equations