A silicon slice constant-pressure application clamp of a plasma etcher comprises a clamp body, vertical column screws, return springs, a pressure plate, tightening nuts and a numerical control torque wrench. The lower ends of the two vertical column screws are fixed onto the clamp body; threads are arranged on upper sections of the two vertical column screws; the return springs are sleeved on the upper sections of the two vertical column screws; the pressure plate is sleeved on the two vertical column screws and tightened by the tightening nuts; and the tightening nuts are tightened by the numerical control torque wrench in a constant-torque manner. As a whole stack of silicon slices is placed between the clamp body and the pressure plate tightened by the two tightening nuts through the numerical control torque wrench in the constant-torque manner, constant-pressure application of the pressure plate to the whole stack of silicon slices is realized. Accordingly, the pressure of the whole stack of silicon slices can be controlled precisely, and unevenness of stress on the peripheries of the silicon slices can be reduced, so that products are uniform in performance and fine in etching effect.