Fixing method of concrete drainage ditch expansion joint foam board

The invention relates to a drainage ditch construction technology of constructional engineering, and provides a fixing method of a concrete drainage ditch expansion joint foam board. The fixing method comprises the following steps that 1, foam board fixing frames are manufactured by adopting cement mortar; 2, the two foam board fixing frames are vertically and oppositely arranged, the front surface and the back surface of the foam board are coated with adhesive water, then the foam board is placed between the two foam board fixing frames, and a foam board fixing device is formed through fixing; 3, before concrete pouring of a drainage ditch, the spliced foam board fixing device is subjected to mortar setting by using cement mortar, so that the foam board is accurately located at the position of an expansion joint; and 4, a formwork is installed, the drainage ditch is poured by using concrete, the foam board fixing device is poured and covered together, vibration and compaction are carried out, and the drainag