  A universal amplification scheme of ultra-small phase based on weak
measurements is given and a weak measurements amplification based laser
interferometer gravitational-wave observatory (WMA-LIGO) is suggested. The
WMA-LIGO has potential to amplify the ultra-small phase signal to at least
$10^{3}$ order of magnitude such that the sensitivity and bandwidth of
gravitational-wave detector can be further improved. Our results not only shed
a new light on the quantum measurement but also open a new way to the
gravitational-wave detection.
