The invention discloses an on-board equipment plug-and-play test interface circuit and a method for realizing plug-and-play data transmission and belongs to the field of satellite testing, aiming to solve the problem that test interfaces utilized between existing satellite ground test devices have no plug-and-play support functions and are low in test speed, thereby going against realizing plug-and-play between the on-board equipment and the ground test devices. A detection signal input end of a control circuit is connected with a detection signal output end of a connection state detection circuit, a power supply signal output end of the control circuit is connected with a power supply signal input end of a power supply output circuit, and a communication control signal input or output end of the control circuit is connected with an output or input end of a data transmission circuit. The detection circuit is used for detecting connection states between an on-board interface unit and a test circuit interface, the power supply output circuit is used for providing work power supply to the test circuit, and the data transmission circuit is used for realizing data interaction with the test circuit. The on-board equipment plug-and-play test interface circuit and the method for realizing plug-and-play data transmission can be applied to satellite testing technology.