  In this letter, we show that the dimensionless parameter in the generalized
uncertainty principle (GUP) can be constrained by the gravitational wave event
GW150914, which was discovered by the LIGO Scientific and Virgo Collaborations.
Firstly, according to the Heisenberg uncertainty principle (HUP) and the data
of gravitational wave event GW150914, we derive the standard energy-momentum
dispersion relation and calculate the difference between the propagation speed
of gravitons and the speed of light, i.e., $\Delta \upsilon$. Next, using two
proposals regarding the GUP, we also generalize our study to the quantum
gravity case and obtain the modified speed of gravitons. Finally, based on the
modified speed of gravitons and $\Delta \upsilon$, the improved upper bounds on
the GUP parameters are obtained. The results show that the upper limits of the
GUP parameters $\beta_0$ and $\alpha_0$ are $2.3 \times 10^ {60}$ and $1.8
\times 10^{20}$.
