Shale gas is regarded as a vital alternative energy resource to boost natural gas reserves and production in China. Problems such as high initial production, mid-late stage wellbore liquid loading and rapid production decline are widely encountered in shale gas wells. The long-term stable production and estimated ultimate recovery (EUR) of gas wells are severely impaired. Tubing deepening is adopted as a low-cost and high-efficiency drainage gas recovery measure. The risk of wellbore liquid loading can be effectively alleviated by this method. Most existing studies on its parameter optimization are performed based on steady-state simulation or single inlet conditions. The actual flow conditions under the complex wellbore structures of deep shale gas wells cannot be accurately characterized. Downdip and updip shale gas horizontal wells were selected as the research objects. A transient multiphase flow model considering multi-point liquid inflow and gas-liquid two-phase flow in the tubing-casing annulus was established. The effects of different tubing setting depths on the production performance of gas wells at different stages were systematically simulated. The start-up pressure is increased by greater tubing setting depth for all well types in the well start-up stage. Slug flow is effectively suppressed, and wellbore liquid holdup and pressure drop are reduced by deep tubing setting in downdip wells during the stable production stage. Lower gravity energy consumption, liquid holdup and pressure drop are realized by shallow tubing setting in updip wells. The continuous production time of downdip wells is prolonged with the increase of tubing setting depth in the late production stage. An increase of about 20.73% is achieved when the tubing is set to Target B compared with Target A. The continuous production time of updip wells is shortened with the increase of tubing setting depth. An increase of up to 20.88% is obtained when the tubing is set to Target A compared with Target B.