【Abstract】 Objective To grasp the dynamic change of the population distribution and seasonal fluctuation of cockroach in Dalian. Methods The baits and traps method was used in the surveillance. Results There were 3 species of cockroaches, and Blattella germanica was the dominant species, accounting for 96.89%. Periplaneta japonica and P.fuliginosa accounted for 3.02% and 0.09% respectively. The activity peak of the cockroach was from July to  October. The order of cockroach distributed in different trade was farm produce trade market, residential area, restaurant, hotel and hospital. Conclusion B.germanica was the dominant species in Dalian, suggesting that it should put the emphasis on the control of it in the future.