The invention provides a self-adaptive grinding method for the inner wall faces of arc head rotary bodies. The method includes the following steps that the range of x-direction contact force Fx is set, and the range of y-direction contact force Fy is set; it is kept that the axis of a grinding head (1) is parallel to the axis of a machined workpiece (6), and the grinding head (1) and the machinedworkpiece (6) rotate in opposite directions; the grinding head (1) moves in the y direction at the speed Vy, when Fy is larger than or equal to N3, Vy is reduced to 0, and the grinding head (1) startsto move forwards in the x direction at the speed Vx; it is kept that Fy is larger than or equal to N3 or smaller than or equal to N4 and Fx is larger than or equal to N1 or smaller than or equal to N2 during grinding; and when the axis of the grinding head (1) coincides with the axis of the machined workpiece (6), after the grinding head (1) continues to carry out grinding by two circles, the grinding head (1) stops rotating. The grinding method has the beneficial effects that the efficiency is high, and the quality consistency of ground products is good, and is suitable for grinding the wallfaces of rigid and flexible rotary bodies.