Abstract: Cracks easily turn up in the applying of the concrete water conservancy projects. It does harm to the buildings, and serious cracks will affect the safety of the buildings. The mending methods are different to dissimilar cracks. The mending methods most in use are daubing on the surfaces, pasting and mending on the surfaces, spraying slurry, embedding and mending after cutting slots, grouting, prestressed anchoring and so on. In the practical projects, we can use only one mending method, or jointly apply more ones.