Disclosed is a dual wafer stage switching system for a lithography machine. The system comprises a base stage (30), a wafer stage (16.1) running at a pre-processing workstation, and a wafer stage (16.2) running at an exposure workstation. A rotating motor (41) is mounted under the base stage (30) for rotating the two wafer stages after the wafer stages have completed pre-processing and exposure operations in order to complete position switch of the wafer stages, wherein the base stage (30) is kept stationary during the switch. The present invention avoids rotation of a large inertia base stage and has low requirement for motor power, while eliminating a guide rail docking device and an auxiliary device and greatly simplifying system configuration. The system is easy and convenient to operate and easy to control.