About one hundred gravitational wave (GW) events have been detected by LIGO/Virgo, most of which (>90%) are from binary black-holes (BBH). Thus, we have opportunities to testing general relativity (GR) in the strong gravity regime. Generally, in GW data analyses, we do not consider effects of charge since it is often thought to be negligible for an astrophysical BH. However, according to the ‘no hair’ theorem in GR, a BH is fully characterized by its mass, spin, and charge. The information of these parameters is unambiguously encoded in the GW signals emitted by the BBH merger events. Therefore, it is important and meaningful to study the effects of BH charge on GW signals. In this talk, I will show results of my recent research on it.