Using a new pulsar timing system at the 25-m radio telescope of Urumqi Astr
onomical Observatory, we have detected a large glitch in the Crab pulsar wh
ich occurred in 2000 July. The size of the glitch is Deltav/v similar to 2.
4 x 10(-8), with a relative increment in frequency derivative Delta (v) ove
rdot / (v) over dot similar to 5 x 10(-3). The observing system is introduc
ed and the observed properties of the glitch axe discussed.