According to the design and manufacture needs of typical automobile brake disc dimension and form and location tolerance, the detection method of brake disc dimension and form and location tolerance with automatic device was discussed. The working principle of laser distance sensor and detection method for brake disc depth were analyzed, and the distance sensors layout of automatic detection device was proposed. Mechanical structure, electrical system and operation process of the automatic detection device were designed. Calculation formulas of main detection items such as diameter, depth, flatness, parallelism and run-out were derived. It provides an automatic solution for brake disc dimension and form and location tolerance detection.