The invention discloses a water well mouth adjustment device. A first single-rotation connector and a first dual-rotation connector are connected through a first short connecting rod. The other end of the first single-rotation connector is connected with a front short connecting rod. The other end of the first dual-rotation connector is connected with a first long connecting rod. The other end of the first long connecting rod is connected with a second single-rotation connector. The other end of the second single-rotation connector is connected with a second short connecting rod. The other end of the second short connecting rod is connected with a third single-rotation connector. The other end of the third single-rotation connector is connected with a second long connecting rod. The other end of the second long connecting rod is further connected with a fourth single-rotation connector. The other end of the fourth single-rotation connector is connected with a third short connecting rod. The other end of the third short connecting rod is connected with a fifth single-rotation connector. The other end of the fifth single-rotation connector is connected with a rear long connecting rod. According to the water well mouth adjustment device, the inclination, caused by ground surface settlement, of a well mouth and a pipeline can be effectively adjusted; and deformation, cracking and incomplete sealing of a well mouth pipeline are avoided, and normal production of a water well is guaranteed.