An apparatus for obtaining a relationship between a degree of cure and a volume shrinkage ratio of a packaging material, comprising: an upper load module provided at a top of the apparatus and including an upper servo motor, an upper ball screw and a force plate, with the upper servo motor configured for driving the upper ball screw into rotation via a belt, such that the force plate coupled to the upper ball screw moves downward to be positioned in place; a lower load module provided at a bottom of the apparatus and including a lower servo motor, a lower ball screw and a load joint group having a push rod, with the lower ball screw configured for being driven by operations of the lower servo motor, such that the load joint group coupled to the lower ball screw creates a corresponding displacement; an upper limiter module coupled to the force plate of the upper load module; and a lower cavity module provided on the lower load module for partially and slidably receiving the push rod of the load joint group, with the push rod configured for moving up with the displacement of the load joint group, wherein the lower cavity module includes a cavity and a heating pipe configured for heating and maintaining a subject to be measured in the cavity at a constant temperature, wherein the upper load module is configured for moving down by the force plate and the push rod is configured for moving up in the lower cavity module, such that a constant pressure is applied to the subject to be measured in the cavity, wherein the lower load module further comprises an optical measuring unit provided on the lower load module near the cavity for measuring the displacement of the load joint group, wherein a change in volume per unit time of the subject to be measured is calculated based on the measured displacement of the load joint group, and wherein the apparatus further comprises a data processing module connected to a controller and configured for calculating a volume shrinkage ratio of the subject to be measured based on the change in volume of the subject to be measured, and further configured for obtaining a predetermined relationship graph of degree of cure versus time under a constant temperature of the reaction kinetics model, and further configured for calculating a relationship graph of volume shrinkage ratio versus time, wherein the data processing module is further configured for combining the relationship graph of degree of cure versus time of the reaction kinetics model and the relationship graph of volume shrinkage ratio versus time to calculate relationship between the volume shrinkage ratio and the degree of cure of the subject to be measured. an upper load module provided at a top of the apparatus and including an upper servo motor, an upper ball screw and a force plate, with the upper servo motor configured for driving the upper ball screw into rotation via a belt, such that the force plate coupled to the upper ball screw moves downward to be positioned in place; a lower load module provided at a bottom of the apparatus and including a lower servo motor, a lower ball screw and a load joint group having a push rod, with the lower ball screw configured for being driven by operations of the lower servo motor, such that the load joint group coupled to the lower ball screw creates a corresponding displacement; an upper limiter module coupled to the force plate of the upper load module; and a lower cavity module provided on the lower load module for partially and slidably receiving the push rod of the load joint group, with the push rod configured for moving up with the displacement of the load joint group, wherein the lower cavity module includes a cavity and a heating pipe configured for heating and maintaining a subject to be measured in the cavity at a constant temperature, wherein the upper load module is configured for moving down by the force plate and the push rod is configured for moving up in the lower cavity module, such that a constant pressure is applied to the subject to be measured in the cavity, wherein the lower load module further comprises an optical measuring unit provided on the lower load module near the cavity for measuring the displacement of the load joint group, wherein a change in volume per unit time of the subject to be measured is calculated based on the measured displacement of the load joint group, and wherein the apparatus further comprises a data processing module connected to a controller and configured for calculating a volume shrinkage ratio of the subject to be measured based on the change in volume of the subject to be measured, and further configured for obtaining a predetermined relationship graph of degree of cure versus time under a constant temperature of the reaction kinetics model, and further configured for calculating a relationship graph of volume shrinkage ratio versus time, wherein the data processing module is further configured for combining the relationship graph of degree of cure versus time of the reaction kinetics model and the relationship graph of volume shrinkage ratio versus time to calculate relationship between the volume shrinkage ratio and the degree of cure of the subject to be measured.