The generation of pulse bundles and bundle groups are investigated in a mode-locked Thulium-doped fiber laser modulated by nonlinear polarization ro ta tion.Stable bound pulse bundles with a duration from 30to 50ns are generated from the cavity in which nonlinearity and dispersion are enhanced by inserting t wo pieces of SMF-28with lengths of 100m and 350m,respectively,into a ring c avity.One bound pulse bundle can produce up to 12sub-pulses with varying ampl i tudes but the same time interval.It is found that by rotating the polarization controllers,the pulse duration and the number of sub-pulses of a bound bundle c an be adjusted,furthermore,some of them can be expelled from the bundle to for m a bundle group.Inside the bundle group,its distribution is regularly organiz ed with quasi-quantized separations,where the pulse duration is 2.8ns.Stable second harmonic mode-locking pulse bundles are generated as well.In this case, the pulse bundle is found to present a combination of multiple pulse forms.