Abstract:A method of increasing the measuring precision is introduced,the time interval is measured using the high precision,time interval measurement chip TDC-GP2’s second measuring range,the problem of lacking measuring range can be avoided by time delaying;The time measurement of less than a clock period can be solved by the merit of the simulation method,in order to solve the nonlinearities in the time interval measurement,the A/D convert method is introduced,and the result of the experiment show that the measuring precision is improved effectively.