A boundary scan test method is used to test connectivity of a pad having a direct connection to user logic. The method comprises the following steps: configuring an FPGA to enter a test mode; generating by means of user logic, a boundary scan chain for a boundary scan test; loading a boundary scan test instruction to the FPGA, and loading a PRELOAD instruction to a device having a pad to be tested for connectivity; sending, via a TDI port, a first test vector to the pad; performing the boundary scan test, and loading an EXTEST instruction to the device having the pad; and removing first response data from a TDO port, and performing response analysis and fault diagnosis.