Abstract: Sensitivity tests for the initial field and open boundary of numerical model based on the Finite Volume Coastal Ocean Model (FVCOM) were carried out using 7 sets of initial temperature and salinity fields, 5 sets of open boundary conditions from ocean reanalysis data sets and observations of temperature and salinity. A bifurcation angle indicator was introduced to describe the bifurcation characteristics of the Yellow Sea warm current, and wavelet and power spectrum analysis methods were used to study the intra-seasonal variability of the bifurcation angle in winter. It shows that the numerical results of FVCOM are most reliable when the reanalysis data of the eddy solving high precision ocean model (OFES) were used as the initial field of temperature and salinity, and the data of simple ocean data assimilation information (SODA) were used as the open boundary condition. The bifurcation angle indicators can well describe the changes of the Yellow Sea Warm Current, and it has strong period of 3 days, 5 days, and 8 days due to the influence of wind fields.