This paper presents improvements on a multichannel time interval measurement for Time Comparison. The measurement has eight channels and measurements the time interval between nine clocks at the same tine. The measurement design is based on a commercially available GPX ASIC from acam-messelectronic gmbh provides a maximum of 86ps resolution per channel. In this measurement precision the measurement range of system is less than 10us and goes beyond the requirement of the time comparison. We extend the measurement range to endless by the internal start re-trigger and external interrupt. The architecture details of this system as shown in figure 1. We also develop a software runs on pc can control the measurement and display the measurement result in real time. We analyze the resolution variation of the measurements and the present linearity plots finally. The calculate results indicate that the precision per channel just a little decline after the measurement range was extended.