In order to explore the microstructure of interstitial channels along meridians in vivo confocal laser imaging system is used to observe the midline of the inner abdominal wall which is the accumulation site of sodium fluorescein in interstitial channels along conception vessel in rats. The tracks of sodium fluorescein aggregation on the surface of inner abdominal wall of rats after sodium fluorescein injection via caudal vein is determined by fluorescence photography. In vivo confocal laser imaging system is used to observe the structural differences between different sites on the tracks of sodium fluorescein along the midline of inner abdominal wall and its adjacent open sites. The results are compared with those of the Masson staining in vitro. It is found that a lot of fibrous tissue parallels to the midline in the interstitial channel along the inner abdominal wall and arranges in order in rat, which is rich in tissue fluid. The fibers on the surface of side muscle tissues are not parallel to the midline. A large number of parallel fiber structures in the interstitial channels along the conception vessel provides a histomorphological basis for the convergence of interstitial fluid to the midline of abdominal wall and the interstitial flow along it. It provides a new method and evidence for the visualization of meridian running and structure. It is of great significance for the exploration of the biological connotation of meridians.