The invention discloses a detecting system comprising a semitrailer, detecting equipment and an auxiliary stand. The detecting equipment can be detachably assembled on the semitrailer through the auxiliary stand, and the semitrailer is a driven trailer with no driving source. Compared with the prior vehicular detecting system, the detecting system of the invention has the advantages that the detecting equipment can be detachably and rapidly assembled on the semitrailer through the auxiliary stand. In addition, the semitrailer is the driven trailer with no driving source, thus the whole detecting system has low cost.