J-tube provides external protection for submarine cables to avoid large movement and deformation under wave and current loads. However, due to local scouring of the seabed during the operation period, the location of the submarine cable's mud outlet is changed, resulting in free spanning of the submarine cable, which affects its structural strength.?OrcaFlex software is used to establish an analysis model. For the environmental parameters under different local scour depths and return periods, the nonlinear time domain method is used to evaluate the structural state of submarine cables.?According to the calculation results, the environmental conditions of different scour depths and return periods have a great impact on the structural strength of the submarine cable. The minimum bending radius of the submarine cable is a limit condition, which occurs in the bell mouth area of the J-tube.?Under the environmental conditions of 1-year return period and 100 year return period, the extreme points of minimum bending radius corresponding to different scour depths are different.