Abstract: Trace design is the key of trenchless horizontal directional drilling pipe laying engineering, the paper makes a deep research on the trace optimization design with dynamic programming theory. According to the effective demand of engineering,a set of HDD software is designed,which realizes functions as the trace optimization design,working drawing design,built drawing treatment, construction record fills-in,trace position search etc, integrates the design,optimization and drawing as a whole. Practice shows, that software can satisfy the request of horizontal directional drilling engineering well.