Abstract: A method and device for testing a positioning and speed measuring system main unit. The method includes: obtaining a first simulation signal by simulating an absolute position sensor and a relative position sensor; sending the first simulation signal to a main unit of a to-be-tested positioning and speed measuring system; obtaining a first result calculated by the main unit based on the first simulation signal; obtaining a second result calculated based on the first simulation signal, the second result being a reference result corresponding to the first simulation signal; and determining that the main unit is abnormal if a comparison between the first result and the second result exceeds a first preset range. Therefore, the main unit can still be tested without components including absolute position sensors and relative position sensors, the test process is simple and easy to implement, a test environment can be built without large-scale investment.