Begin with the density matrix equations of motion under the conditions of the rotating wave,slowly varying amplitude and mean field approximations,by using the numerical calculation results,the time evolution laws of the probe laser field and populations corresponding to two cases in producing inversionless lasing (i.e.,through the Pitchfork bifurcation giving rise to continuous wave lasing emission and through the Hopf bifurcation giving rise to self-pulsing lasing emission) in an open V-type resonant system are studied,and the effects of the system parameters varying on the time evolution laws are discussed.