Abstract: A chemical plant was suffered greater damage after a fire hazard. In order to eliminate the hidden danger of the structure，the safety detection and evaluation of structure were taken. Temperature distribution of the fire and temperature of the structural components were deduced，the properties of steel and concrete after fire were tested，and damage extent of the structural components were evaluated. Based on the results，detailed strengthening scheme was put forward. The structure could completely meet the requirements of the bearing capacity and durability after strengthening by the scheme.