The invention discloses a balanced shield mud air-pressure cabin opening pressure maintaining and wall protecting construction method for shield tunneling. The method includes the steps that balanced shield mud is prepared, and the balanced shield mud is injected to the outer sides of shield segments through pressure to form seal rings; the balanced shield mud is injected to the outer side of a shield machine body through pressure; residue soil in a soil cabin is replaced by the balanced shield mud; a shield machine retracts after replacement, and a gap between a shield machine cutterhead and a tunnel face is filled with the balanced shield mud to form a mud wall with the thickness equivalent to the retracting distance; pressure is increased in a graded mode; and gas replacement is carried out. According the construction method, ground reinforcing is not needed, the novel balanced shield mud is adopted, difficulties in cabin opening operation of shield tunneling under buildings, at river bottoms with hydraulic connection, at water-rich fault zones and in unconsolidated formations are overcome, and difficulties in cabin opening operation of shield tunneling under special unstable stratums are overcome.