The invention relates to the technical field of underground engineering construction, in particular to an earthwork excavation method under a pipe curtain. The problems that in the pipe curtain methodconstruction process of an existing soft soil area, the construction technology is complicated, more potential safety hazards exist, and disturbance influence on upper soil bodies is large are solved. The earthwork excavation method comprises the following steps that soil bodies under the pipe curtain are subjected to grid-type freezing construction, soil bodies in first block areas and second block areas are sequentially excavated in an alternative bay excavation mode, and temporary supporting devices are mounted between the top and bottom frozen walls of the block areas; and the soil bodiesin the middles of the top frozen walls are excavated, and first supports are mounted; remaining soil bodies on the two sides of the top frozen walls are excavated, second supports are mounted on thetwo sides of the first supports correspondingly, and thus the tops of the temporary supporting devices abut against the second supports; the side face frozen walls between the first block areas and the second block areas are excavated, a third support is mounted between every two adjacent second supports, and the first supports, the second supports and the third supports are connected to form a whole horizontal support; and in this way, earthwork excavation and supporting construction are gradually carried out in the length direction of the pipe curtain.