Abstract: Taking thermal insulation layer of concrete face slab behind dam of a water conservancy project in Xinjiang as an example，a kind of anti crack mortar without curing was developed.Water binder ratio of the anti cracking mortar was 22%，content of fly ash（grade I）was 10%，unit water consumption was 13 kg/m3，content of water reducer was 2%，cement P.O42.5R，quartz sand （fineness modulus was 2.3），compressive strength was 25.3 MPa and flexural strength was 5.1 MPa after 3 days of construction.It had good adaptability with insulation board and was suitable for thermal insulation protection of concrete surface of hydraulic structures in severe cold areas.Construction technology of thermal insulation board for concrete panel of hydraulic building was introduced.It provided reference for safe operation of hydraulic structures in cold areas.