The work aims to explore the tangential fretting wear mechanism and damage laws of 690 alloy tube through the tangential fretting wear tests of 690 alloy tube/405 stainless steel (tube-on-plate configuration). The effect of normal force (10 N, 20 N and 40 N) on tangential fretting wear of 690 alloy tube/405 stainless steel seismic strip was studied by self-made multifunctional composite fretting wear tester. The friction coefficient and dissipated energy were analyzed to obtain the dynamics information during the test. Then, the wear scars were examined through optical microscope and scanning electron microscopy to obtain wear mechanism and damage laws. When the displacement amplitude was 100 μm and 200 μm and the normal force was 10 N, 20 N and 40 N, the fretting state of 690 alloy tube/405 stainless steel block was in the complete slip zone. With the increase of normal force, the friction dissipation energy and friction force increased, the damage of 690 alloy tube was intensified, the wear debris increased, the delamination pits on wear scar surface decreased due to be covered with wear debris and the friction coefficient showed the decrease trend. Along the fretting direction, the contents of O, Cr, Fe and Ni were serrated and the wear depth was also serrated along the motion direction due to the line contact, which was caused by non-ideal plane of 690 alloy tube and 405 stainless steel block. Overall, the wear volume of 690 alloy tube and 405 stainless steel block increases with the increase of normal force. The main wear mechanism of 690 alloy tube is delamination and abrasive wear.