In this Letter, we describe an optical assembly that is designed for the engineering application of the atomic laser cooling techniques. Using a folded optical path scheme, we have built a miniaturized, compact magneto-optical trap (CMOT) for an ${}^{87}\mathrm{Rb}$ atomic fountain clock. Compared with the conventional magneto-optical traps used in other clocks, our system is more robust, more compact, more stable, and saves about 60% laser power. This optical setup has operated for about a year in our fountain system, passed the thermal cycle tests and the mechanical vibration and shock tests, and maintained a high performance without a need for realignment.