The testing system for measuring ADSL cable breakpoint based on TDR(time domain reflection)is introduced.The system uses STC-MCU as a control core,and FPGA as test main body to transmit and receive pulse,and collects the trip time of pulse in ADSL cable,so that the system realizes the ADSL cable breakpoint measurement.On the basis of ana-lyzing the actuality of the instrument products,the main design theory is illuminated,and then the system design diagram,the hardware implementation,the software test flow and the actual test results are introduced.The experiments show that the tester is able to test breakpoint quickly and accurately.Only sheared appropriately,the system design is used in other instruments as an embedded module.