This paper describes a mathematical model developed to study the behavior of LPG tanks when subjected to jet fire. The model consists of a number of field and zone sub-models which are used to simulate the various physical phenomena taking place during the tank engulfment period. The comparisons between the model predicted results and the test data showed better agreement. The results showed that the jet fire partially impingement on tank wall led to higher wall temperatures and the time to failure was shorter than in engulfing pool fire. And the fire exposure started at the vapor wall is under more dangerous situation than the fire exposure at the bottom of the tank.