Using the mesoscale TJ-WRF model, we studied the influence of Tianjin urban heat island effect on the sea breeze (front) circulation triggered local thunderstorms which tend to occur in urban areas by changing the land use type of the underlying surface in the sensitivity numerical simulation tests. The results show that the effect of urban heat island is different due to the different types of urban underlying surfaces. The urban heat island effect is more obvious and the impact scope is expanded when the land type of suburb surface is changed to urban and built-up land; when the urban surface is changed to dry land and pasture, there is no urban heat island effect near Tianjin City. At the same time, we can see that when there is urban heat island effect near urban area of Tianjin, the sea breeze (front) circulation is strengthened and its speed is accelerated. So, the more obvious the urban heat island effect is, the more obvious the strengthening and acceleration of the sea breeze (front) circulation is. The speed of the sea breeze (front) is faster than the speed without urban heat island by 9.3 km·h-1. But when it moves near the city and encounters the urban heat island circulation, the sea breeze (front) circulation is blocked and its speed slows down quickly. And the north-south branch flowing and climbing up of its rear airflow becomes obvious. The convergence and upward motion are also enhanced when the two circulations meet and superimposed. The more obvious the effect of urban heat island is, the more obvious the blocking effect of sea wind (front) circulation is, the slower down the speed of the sea breeze (front) circulation is, and the stronger the convergence and upward motion are when the two circulations meet and superimposed.In addition, when sea breeze (front) circulation moves toward the city, it will result in the decrease in temperature and the increase in moisture content of the lower-level air. However, due to the existence of the urban heat island effect, the thickness of the wet air layer in the airflow after the sea breeze (front) circulation is greatly reduced, and the more obvious the effect of the urban heat island is, the more obvious the thickness of the wet air layer decreases.