InGaAsP microdisk lasers are fabricated on AlxOy by wafer fusion, Room-temperature continuous-wave operation with threshold pump power of 1.13 mW has been achieved from a 2.2-mu m diameter microdisk laser. The lasing wavelength with incident pump power redshifts at a rate of 0.28 mm/mW which shows the improved thermal characteristics due to the high thermal conductivity of AlxOy bottom layer.