The steering-stability of the t rain of towed how it zer is analysed in this paper. A dynamic model, the mathematic expression of steady turnability of towed how itzer and an evaluation method for turning stability are presented. It is considered that the turning stability of the train lies on the stability factor K 1 of tow ing vehicle , that is, only if K 1 is greater than 0 the train can turn stably. The result show s that the weig ht of how itzer m2 and the distance L betw een how itzer and tow ing vehicle have some ef fects on factor K 1 . In designing towed howit zer, the compromise betw een m2 and L should be considered to keep K 1 less than 0.