In order to improve the system density of integration and maintain the precision simultaneously, Field Programmable Gate Array (FPGA) delay-line interpolator is introduced to realize pulsed laser ranging with high time resolution and precision. The method is based on clock circle dived principle. The time errors in direct digital counting method are converted to digital flash-code by latching the output of FPGA delay cells. Then a latch method for latching the delay cell signals was proposed based on the high frequency clock (400 MHz). The corresponding time-to-digital interpolation converter and delay cell time measurement were also designed. The measurement shows that single-shot resolution can be improved to 80ps, and average resolution can reach 40ps (mm level). Applied in pulsed laser range finder, the distance results are given and the error of FPGA interpolation method is analyzed in theory. Finally, the precision of ±10 centimeter level is achieved.