The invention discloses a support type suspension rack detection device. The detection device comprises a base (1), a fixingrotary assembly (3) and a coaxiality detection mechanism. A circular hole (2) is formed in the top face of the base (1). The fixing rotary assembly (3) is used for fixing a damper oil storage barrel (4) and is used cooperatively with the circular hole (2). The coaxiality detection mechanism comprises a support rod (5), a guidance sleeve (6), a sliding rod (7) and a detection pen (8). The guidance sleeve (6) is fixed on the top of the base (1) through the support rod (5). The sliding rod (7) is in insertion connection with the guidance sleeve (6) and is capable of freely sliding along the guidance sleeve (6). A fixed ring (9) is arranged on one end, close to the circular hole (2), of the sliding rod (7). The detection pen (8) is inserted into and fixed on the fixed ring (9). According to the invention, the coaxility of a damper and a spiral spring can be effectively detected and the detection device is advantaged by high detection efficiency.