For better understanding the expansion order effect on the residual contact pressure between tube and tubesheet, numerical simulations of multi-tubes expansion were performed by using ANSYS software. Two sets of different materials of tubes and tubesheets under different expansion orders have being analyzed in the present paper. The simulation results show that the residual contact pressure between one tube and the tubesheet decreases with the increasing number of expanded tubes around it, and reaches a certain value gradually. The expansion order of “top to bottom, left to right” which is used in the actual production process can provide a higher residual contact pressure than other expansion order by comparing the results of two different expansion orders. The material properties of tube and tubesheet have significant influence on the residual contact pressure when the expansion pressure is the same.