Abstract: The present disclosure provides a method for constructing a time-varying constitutive model of a seawater-aged GINA gasket for an immersed tube tunnel and relates to the technical field of research of immersed tube waterproof equipment. The method includes the following steps: obtaining stress relaxation curves at different aging temperatures; determining an aging performance change value P of rubber used for a GINA gasket; determining a stress-strain relation curve of the GINA gasket; obtaining a stress-strain relation curve of a full aging cycle; and constructing a constitutive model of stress relaxation and seawater aging of the GINA gasket. According to the present disclosure, a service state of the GINA gasket can be dynamically monitored, which provides a basis for service life evaluation of the GINA gasket and early warning on a risk of the GINA gasket.