The invention discloses an excavator, a bucket hydraulic system of the excavator and a method for controlling the bucket excavating speed of the excavator. The bucket hydraulic system of the excavator comprises a bucket hydraulic cylinder (1) and a reversing valve (2), the bucket hydraulic cylinder (1) is connected with a main oil inlet path (3) and a main oil returning path (4) through the reversing valve (2), and the bucket hydraulic system of the excavator further comprises a control system. The control system comprises a control device and a pressure sensor (5), the pressure sensor (5) is connected with a rodless cavity of the bucket hydraulic cylinder (1) to detect pressure in the rodless cavity, the control device is connected with the pressure sensor (5), and when the rodless cavity of the bucket hydraulic cylinder (1) performs oil injection and a rod cavity performs oil returning, the control device controls the oil returning flowing speed of the rod cavity of the bucket hydraulic cylinder (1) according to the detection value of the pressure sensor (5) so that the excavating speed of an excavator bucket is controlled.