According to the application characteristics of current hard cable in cementing quality logging in cased wells, a variety of stress state in the logging is analyzed. Based on the principle of mechanical balance, a mathematical model of cable head tension during hard cable logging is established,and the calculation method of cable head tension is put forward.On this basis, the changes of cable head tension are calculated simulatelythrough the VBA programming examples.The influence of cable logging speed, hard cable length, and size structure on the cable head tension and depth are researched. The results show that the parameters of the well body structure is the decisive factor determining the distribution of the cable head tension and the depth of the cable, and the effect of increasing hard cable length and reducing hard cable outer diameter of cable on logging depth is not obvious.