  Kocevski et al. (2003) found that there is a linear relation between the rise
width and the full width of gamma-ray burst pulses detected by the BATSE
instrument based on their empirical functions. Motivated by this, we
investigate the relationship based on Qin et al. (2004) model. Theoretical
analysis shows that each of the two quantities, the rise width and the full
width of observed pulse, is proportional to $\Gamma^{-2}\Delta\tau_{\theta,\rm
FWHM}\frac{R_c}{c}$, where $\Gamma$ is the Lorentz factor for the bulk motion,
$\Delta \tau_{\theta,\rm FWHM}$ is a local pulse's width, $R_{c}$ is the radius
of fireballs and c is the velocity of light. We employ the observed pulses
coming from four samples to study the relationship and find that: (1) Merely
the curvature effect could produce the relationship with the same slope as
those derived from Qin et al. (2004) model in the rise width vs. the full width
panel. (2) Gamma-ray burst pulses, long or short ones (selected from the short
and long GRBs), follow the same sequence in the rise width vs. the full width
panel, with the shorter pulses at the end of this sequence. (3) All GRBs may
intrinsically result from local Gaussian pulses. These features place
constraints on the physical mechanism(s) for producing long and short GRBs.
