Influenced by the collision between India and Eurasia plates, a series of large strike slip shear zones have developed in the Sanjiang area since Cenozoic. In order to determine the shear property and time of the Biluoxueshan-Chongshan-Lancangjiang shear zone, a detailed field geological survey and indoor analysis were carried out in Yongbao Bridge, Yongping County, Dali City of Chongshan shear zone. The observation data show that the left strike slip shear feature is obvious. Meanwhile, the LA-ICP-MS zircon U-Pb age of migmatized felsic veins in Chongshan shear zone is 24.6 ± 2.0 Ma, indicating that the belt was in the stage of strike slip shear anatexis in the late Oligocene. Combined with the previous research results, under the condition of Cenozoic shear compression strain decomposition, the north of Biluoxueshan, Biluoxueshan-Chongshan section and Lancangjiang section are characterized by right strike slip, left strike slip and right strike slip respectively.