  The measurement of the Hubble constant $H_0$ plays an important role in the
study of cosmology. In this letter, we propose a new method to constrain the
Hubble constant using the strongly lensed gravitational wave (GW) signals. By
reparameterizing the waveform, we find that the lensed waveform is sensitive to
the $H_0$. Assuming the scenario that no electromagnetic counterpart of the GW
source can be identified, our method can still give meaningful constraints on
the $H_0$ with the information of the lens redshift. We then apply Fisher
information matrix and Markov Chain Monte Carlo to evaluate the potential of
this method. For the space-based GW detector, TianQin, the $H_0$ can be
constrained within a relative error of $\sim$ 0.3-2\%, using a single strongly
lensed GW event. Precision varies according to different levels of
electromagnetic information.
