The invention provides a heat insulation jacket of a catalytic converter, a manufacturing method of the heat insulation jacket and a heat insulation structure. The heat insulation jacket of the catalytic converter is applied to an automobile exhaust system. The heat insulation jacket of the catalytic converter comprises a catalytic converter part heat insulation jacket used for being arranged on the catalytic converter in a sleeving manner. The catalytic converter part heat insulation jacket is provided with an opening in the axis direction of the catalytic converter and comprises a body section and a necking section connected with the body section. The cross section area of the necking section is smaller than that of the body section. One end of the necking section forms a gas pipe opening allowing an exhaust pipe/tail pipe to pass through. The catalytic converter part heat insulation jacket is arranged on the catalytic converter in the sleeving manner, a pipe part heat insulation jacket is arranged on the exhaust pipe in a sleeving manner, and the catalytic converter part heat insulation jacket and the pipe part heat insulation jacket conduct heat insulation on the catalytic converter and the exhaust pipe correspondingly. The catalytic converter part heat insulation jacket and the pipe part heat insulation jacket are tightly and firmly attached to the catalytic converter andthe exhaust pipe correspondingly, the shock resistance is high, and the catalytic converter part heat insulation jacket and the pipe part heat insulation jacket will not be damaged or disengaged evenif an automobile continuously runs for 50 days or over in a hostile environment.