The invention discloses a synchronous grooving and plastic laying all-in-one machine which comprises a walking track, a hydraulic system for providing power for the synchronous grooving and plastic laying all-in-one machine, a grooving mechanism and a plastic laying mechanism. The grooving mechanism comprises a drill rod, a hydraulic arm, a grouting system and a sand draining system. The synchronous grooving and plastic laying all-in-one machine can achieve all cross section continuous grooving and plastic laying construction in the horizontal direction, the effective width of grooving is controllable, the problems that grooving and plastic laying are separated from each other on the limited construction site during construction of an existing device, an initial grooved section cannot undergo plastic laying, plastic laying connectors are many and the construction quality cannot be guaranteed easily are solved, and the synchronous grooving and plastic laying all-in-one machine is particularly suitable for deep layer lateral sealing of sites with deep and thick sand layers, sand inclusion layers or miscellaneous fill.