The traditional digital counting method for time-interval measurement in pulsed laser ranging can't achieve high precision, for it's restricted by the frequency of counting clock. Analog interpolation time-interval measurement has advantages of long measurement range, good linearity and high precision, so it is widely applied for time-interval measurement in pulsed laser ranging. The principle of time-interval measurement by analog interpolation in pulsed laser ranging is introduced. The corresponding time-interval measurement system is designed and studied in experiments. The precision of time-interval measurement reaches up to 100 ps, which corresponds to distance measurement precision at 1.5 cm. In the end, the error of analog interpolation time-interval measurement is analyzed theoretically.