The invention discloses an automobile brake shoe abrasion loss detecting system based on step resistance, which comprises a system testing terminal and a data acquiring and processing system, wherein the system testing terminal adopts four testing sensors (I) of the same structure. Each testing sensor (I) comprises a testing sensor end cover (A), a testing sensor shell (B) and a testing sensor chip (C), wherein the testing sensor chip (C) is mounted into an axial step mounting through hole of the testing sensor shell (B) and fixed by adhesive glue, the lower end face of the testing sensor chip (C) and the lower end face of a hollow screw of the testing sensor shell (B) are coplanar, the testing sensor end cover (A) is fixedly connected with a shell locking annular groove (4) on a hollow bolt head of the testing sensor shell (B) through an end cover locking stop block (1), and a power line and a signal output line of the testing sensor chip (C) penetrate out of an end cover threading hole (2) on the testing sensor end cover (A).