In this paper, aiming at the shortcomings of the current defrosting and icebreaking device of a certain type of rocket cryogenic connector, a new type of rocket cryogenic connector defrost and icebreaker is designed by analyzing the frost generation mechanism on the surface of the low-temperature connector and the influence of ice on the connector shedding and secondary docking, The installation location, structural shape and size specifications of the new device were designed through the analysis of the key defrosting and icebreaking parts on the cryogenic connector. According to the requirements of defrosting and icebreaking of low-temperature connectors during the filling process and temperature return before secondary docking, the air supply flow, gas supply pressure and temperature indicators were set after experimental data and simulation model calculation. Experimental verification shows that the new defrosting and icebreaking device can improve the reliability of low-temperature connector falling off and ensure the safety and effectiveness of secondary docking.