The invention discloses a milling method for the appearance of a complex nozzle shell. The milling method specifically comprises the steps that firstly, a mounting side benchmark is turned; secondly,four holes are drilled; thirdly, the appearance is roughly milled; fourthly, the appearance is subject to fine milling. A dedicated machining tool is designed on the key part, the coordinate conversion is achieved through tool aligning balls, an aligning method capable of achieving alignment one by one is changed into the alignment method capable of achieving batched machining through one-time alignment, the clamping and alignment time is shortened, the product machining time is shortened, and a three-axis device is efficiently used for finishing milling tasks of the complex surface.