The invention provides a retaining device for water conservancy construction with a good fixing effect, comprising three-stage stainless steel telescopic rods, hanging rings, rotary tubes, V-shaped support frames, fixing nuts, adjusting tubes, U-shaped hanging rods, supporting tubes, fixing tubes, disassembly nuts, fastening screws, fastening nuts, mounting seats, cables, stable adjustable fixingseat structures, detachable filter screen structures, location movable drainage retaining structures and height adjustable easy-to-detach fixing cone structures. Square-head nuts, rotary screws, deepgroove ball bearings, retaining fixing seats and anchor bolts are advantageous for increasing the stability and improving the fixing effect, and the positions of the retaining fixing seats can be adjusted for better fixation and installation; U-shaped engagement seats, U-shaped connecting seats and connecting plates are advantageous for adjusting the positions of the U-shaped engagement seats according to the installation and fixation position so as to perform better installation and fixation.