Artificial　Neural　Network　system　can　construct　input-output　relationship　according　to　the　system＇s　input-output　signal,　and　ANN　has　special　characteristics　of　adaptive　learning　while　environment　is　changing.　On　the　basis　of　studying　the　intersection　unblocked　reliability　and　its　interferential　factors,　a　method　of　calculating　the　reliability　by　using　the　technique　of　ANN　is　proposed　and　a　practical　example　of　this　method　is　presented　in　this　paper.