Abstract: Resistance characteristic is a fundamental characteristic of heat exchangers. The flow disturbance generated when the fluid flow across heat exchange tubes is a major factor in the deterioration of the resistance. To obtain the impact of flow around front tubes on the resistance of back rows, this paper conducted experimental studies on resistance characteristics of heat exchangers with different numbers of tube rows（varied from 2 to 10）. In order to obtain the influence rules of tube rows numbers on the resistance characteristic,bundle resistance coefficient was defined and a series of experimental data for different numbers of tube rows were given. Meanwhile, based on the experimental studies on cold resistance characteristics, resistance characteristics formula of classical oval tube for 1 and 1.6 was proposed. The influence rules of tube shapes and arrangement were also studied.