The vane work is a new hydraulic structure for protecting river bank from erosion and it is important to establish reasonable vane design method for proper use of vane works. The influence of the attack angle of secoundary flow towards vanes on scour depth of the bed near outer bank is examined and a correction factor f for it is introduced reasonably to determine the longitudinal spacing ofvanes based on the existing PwRI's design method. Existing two design methods of vanes, PYRI method and IIHR method, are compared from hydraulic and economical stand points on the basis of natural river data. It became clear that PwRI design method is more reasonable and economical than IIHR one, judging from all the aspects of vanes.