With high duty cycle and wide aperture, the Large High Altitude Air Shower Observatory
- Water Cherenkov Detector Array (LHAASO-WCDA) can conduct an unbiased gammaray
sky survey in the energy range from a few hundred GeV to 100 TeV. The sensitivity
of WCDA is as high as a few percent of Crab units, which allow us to monitor the VHE
variability of blazars. Once a flare exceeding the threshold is detected, an alert will be
generated and follow-up analysis could be carried out. In this paper the candidate sources,
the methods and current status of the monitors as well as some prospects of alert issues
in the future will be presented.