Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China
; Guangxi Normal Univ, Dept Phys, Guilin 541004, Peoples R China
; Natl Lab Heavy Ion Accelerator, Ctr Theoret Nucl Phys, Lanzhou 730000, Peoples R China
; Chinese Acad Sci, Inst Theoret Phys, Beijing 100080, Peoples R China
Were-study nucleon pole contribution in J/psi -> N (N) over bar pi decays by including the imaginary part for the propagator of the off-shell nucleon with energy above pi N threshold. It is found that when including the imaginary part in the propagator, the branching ratio of the decay width will descend about 11% compared with the result without including the imaginary part, no matter whether including the off-shell form factors or not. It also leads to a phase of up to 25 degrees for the off-shell nucleon propagator at invariant mass around 1400 MeV. This effect needs to be considered for detailed partial wave analysis of N-* resonances around this mass region.