The geological evolution in the southwestern Chinese Tianshan orogen in NW China is poorly understood because of controversial geochronological results of the low-temperature eclogites. It is likely due to Sm–Nd and Rb–Sr isotopic disequilibrium in different mineral fractions, excess 40 Ar in the high-pressure K-bearing minerals, and multi-stage growths of zircon in U–Pb system. Rutile, as a typical eclogite-facies mineral with high U/Pb ratio, is a feasible candidate to constrain the eclogite-facies metamorphic event. In this study, we measured U–Pb rutile age data using SIMS (Cameca IMS 1280) for low-temperature eclogites from southwestern Chinese Tianshan orogen, NW China. We demonstrate that SIMS is a powerful technique for in-situ U–Pb dating of rutile with U content as low as 1ppm. SIMS U–Pb rutile dating yielded an age of 318±7Ma, which may record the time when the rocks cooled down to the closure temperature of Pb in rutile (ca. 500°C), but should be very close to the time of eclogite-facies metamorphism in terms of common fast exhumation of coesite-bearing eclogite. This new proof strongly suggests a late Carboniferous collision between Kazakhstan–Yili block and Central Tianshan microcontinent.