To explore the effect of undulating angle and normal stress on the shear strength and deformation of the rock with regular saw-tooth joints, direct shear tests were carried out on the limestone samples with different undulating angles under different normal stresses. Subsequently, a shear strength estimation formula was established and verified. The results show that,under the same normal stress, according to the morphological characteristics，the shear stress-displacement curves can be divided into three types：the sliding curve, the sliding-peak curve and the peak curve. The sliding curve and the sliding-peak curve can be divided into nonlinearly slow rising, linear steep rising, and “upward convex” slow rising stage, approximately straight and flat stage. The peak type curve can be divided into nonlinearly slow rising, linear steep rising, “slightly convex” rising, brittle falling and gently descending stage. The failure mode of rock with saw-tooth joints with different undulating angles can be generalized into three failure modes: sliding failure, climbing failure and gnawing failure. The evolution of joint damage under each failure mode can be divided into three stages, i.e., the sliding failure mode can be divided into compaction, friction-over-coming and sliding stage. The climbing failure mode can be divided into compaction, climbing-sliding and plastic flow stage. The gnawing failure modes can be divided into compaction-climbing, climbing-gnawing and gnawing-sliding stage. The shear strength increases with the increase of the normal stress and undulating angle, and the evolution of shear strength still follows M-C criterion.