Results of experimental study on fire resistance of four concrete encased steel (CES) columns are presented. The four columns have the same steel section and reinforcements but different load intensity and load eccentricity, which were the key factors for fire resistance of CES columns under fire condition. The tested results are utilized to study the effect of various parameters on thermal and structural response of CES columns. Spalling of CES columns under fire condition are also investigated. Test results show that CES columns under 3-side heating have higher fire resistance than that under 4-side heating. Also, load ratio and load eccentricity have noticeable influence on the fire resistance of CES columns. In addition, spalling of concrete decreases the fire resistance of CES columns.