A multifunctional automatic wall-face trowelling machine comprises an arc-shaped support, a transverse moving automatic adjusting device and a wall-face automatic trowelling device, wherein the transverse moving automatic adjusting device is fixed on the arc-shaped support, the wall-face automatic trowelling device comprises a scraping plate longitudinal adjusting device, a scraping plate angle adjusting device and a scraping plate up-and-down adjusting device, the scraping plate longitudinal adjusting device is arranged on the transverse moving automatic adjusting device, the scraping plate angle adjusting device is arranged on the upper portion of the scraping plate longitudinal adjusting device and comprises an adjusting arm, one end of the adjusting arm is hinged with a supporting arm, an adjusting device is arranged at the bottom of the adjusting arm, the scraping plate up-and-down adjusting device comprises a speed reduction motor and a transmission device, the speed reduction motor is connected with the transmission device through a transmission shaft arranged at the center, the transmission device is connected with a scraping plate support fixing mechanism, a scraping plate support is arranged on the scraping plate support fixing mechanism, and an upper cutter holder and a lower cutter holder are arranged on the scraping plate support. By the aid of the multifunctional automatic wall-face trowelling machine, rapid trowelling of wall faces can be achieved, and the engineering construction progress is accelerated.