I will review the spin measurement methods for black hole X-ray binary systems, especially the X-ray continuum-fitting method mainly used by our group. The method was initially pioneered by Zhang et al (1997). After the efforts from our group for so many years, it started to deliver the reliable results since 2006. So far we have successfully measured the spins for 9 systems. As one demonstration, I will show the recent spin measurement for Cygnus X-1, which is the first black hole candidate in history, and we found that the black hole is rotating maximally. Some other spin-measurement approaches will be also briefly reviewed and compared.