A time calibration and synchronization technique for joint time and frequency transfer via optical fiber is described. The time synchronization scheme for joint time and frequency transfer based on optical compensation technique and dense wavelength division multiplexer (DWDM) is theoretically analyzed. The verification experiment is achieved via 50 km optical fiber spool in the laboratory, the accuracy of time synchronization is 1.6 ps. The time synchronization via 110 km urban fiber link is described, whose accuracy is 30.0 ps. The source of the error of the synchronization is analyzed.