The process of deflagration to detonation transition (DDT) of epoxypropane is studied in the shock tube. The study aimed to obtain the spectra information about the intermediate products of epoxypropane after fast reaction. In the experiment, by using an advanced intensified CCD spectroscopic detector and self-made electrical single pulse trigger, emission spectra of C2 with bandheads 516.52 nm,512.94 nm, 563.55 nm,558.55 nm,554.07 nm,550.19 nm, and 544.77 nm have been detected in the DDT process of epoxypropane with exposure time of 2 μs. Two vibrational band sequences (Δν=-1，0) of d3∏g-a3∏u are identified. And the experiment is performed many times; from the pressure sign monitored by pressure sensors, it can be nearly confirmed the sameness of DDT in the 500～570 nm region. Furthermore, this experiment indicate that C2 radical is one of the main products of epoxypropane in the DDT process, and the several possible reaction passage are given, too.