Abstract: For metro line No.9 turnout, a finite element analysis model of turnout longitudinal mechanical characteristics is established. Based on model analysis, the most unfavorable train loading position is obtained. The influence of line slope gradient on turnout longitudinal mechanical characteristics under train braking load, temperature load and their combination is studied. Research results show that when the two adjacent bogies of the 3rd and the 4th train compartments are on the switch rail, the turnout stress and displacement are most unfavorable. The longitudinal displacement and longitudinal force of turnout structure will increase linearly with the increase of slope gradient and temperature change. Under the most unfavorable working condition, the rail strength and longitudinal displacement of the turnout on slope gradient of 30‰ can meet the specification requirements.