<p>Tibetan Plateau shear line (TPSL), categorized into two types, i.e., transverse shear line (TSL) and vertical shear line (VSL), is one of the major precipitation systems over the Tibetan Plateau (TP). Previous studies on evolution mechanism of TPSLs mainly focused on individual cases of TSLs, and did not exclude the influence of TP vortices existing on the TPSLs. In this work, 120 cases, including 60 TSLs and 60 VSLs with absence of TP vortices, are selected. The mechanisms underlying the genesis and maintenance of both TSLs and VSLs are investigated. Analyses based on the environmental conditions and potential vorticity (PV) budgets reveal that, for both types of TPSLs, in both genesis and maintenance stages, the horizontal PV flux convergence associated with the wind convergence, and the vertically uneven condensational latent heating contribute to the genesis and maintenance of TPSLs. Particularly, for TSLs, the contribution of heating effect is larger than that of the horizontal PV flux convergence, indicating the dominant role of heating effect in the evolution of TSLs; on the contrary, for VSLs, the contribution of horizontal PV flux convergence is greater than that of the heating effect, demonstrating that the evolution of VSLs is primarily determined by the horizontal PV flux convergence<i>.</i></p>