The Persian Gulf is a semi-closed sea that leads to the Gulf of Oman and open waters through the Strait of Hormuz. the main inflow is the Indian Ocean Surface Water (IOSW), which after circulating in the Persian Gulf, Persian Gulf Water (PGW) is created. It was used 11 stations of a valid data set, temperature and salinity, of wintertime ROPME1992 Crouse, which was prepared from the National Oceanographic Research Institute to investigated temperature and salinity changes by measurements and density, sound speed, and water column stability changes caused by software calculations (Ocean Data View) due to the inflow and outflow of Persian Gulf. The measured stations started from Iranian Waters (Lavan Island) and continued until the United Arab Emirates (Sir Bani Yas Island). The results showed water temperature changes in winter between 17.56°C and 20.25°C, salinity changes from 38.48 psu to 43.93 psu, potential density anomaly changes from 27.47 kg/m3 to 19.32 kg/m3 and the changes of sound speed are 1521.7 m/s to 1528 m/s. Southern shallow waters have lower temperature, higher salinity and density. In density changes, the role of salinity is greater than temperature, but in the changes of sound speed, temperature has a greater contribution in the north of the Persian Gulf and in the south of it, salinity has a greater contribution. The highest speed of sound is related to the north and the lowest is related to the middle and south of the Persian Gulf. Near the coasts of Iran, at the depth more than 30 meters, a subsurface flow of warm water is observed, which is not affected by the surface layers that have cooled in winter, and still has the effected by Indian Ocean Surface Water (IOSW). The presence of CE1 eddy, at station 4, at a depth of about 30 meters is completely visible, which is due to the return of the IOSW flow. Although the water column from station 5 to 9 is mixed and relatively homogeneous, it is horizontally heterogeneous. Also, the results clearly show that the two different flow of IOSW (in the north) and PGW (in the south) cause different water column stability regimes, so that in the northern stations, the diffusive regime and in the southern stations, the finger regime plays a greater role in creating double diffusion convection. In the southern stations, layers consisting of static instability are seen more than layers consisting of double diffusion convection in the water column. In conclusion, the diffusive regime generally plays a greater role in creating double diffusion convection in this cross section of The Persian Gulf in winter.