The relations between the minimum horizontal reinforcement ratio of wall with strength grade of block, mortar, reinforcement and vertical compressive stress were analyzed on the basis of research results abroad. The variant scope of minimum horizontal reinforcement ratio during normal service was derived. It coincides with the current code stipulation. Simplified formula of minimum horizontal reinforcement ratio for wall with ductile shear failure has been provided. At the same time, vertical compressive stress dominant scope is proposed when minimum horizontal reinforcement is needed. This research result can be used as a reference in design.