To explore the effect of the undulating angle and normal stress on the shear strength and deformation of the rock with regular saw-tooth joints, the direct shear tests were carried out on the limestone samples with different undulating angle under different normal stresses. Based on this, a shear strength estimation formula for it was established and verified. The investigation 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 nonlinear slowly rising, linear steep rising, “upward convex” slowly rising stage, approximate straight and flat stage. The peak type curve can be divided into nonlinear slowly 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. That is to say, 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 normal stress and undulating angle, and the expression of shear strength still follows M-C criterion.