The application of “stress concept” in physics to the research of plant resistance has been acceptedwidely. However, a useful mathematical model is still wanting. In this paper the quantitative relationshipamong the freezing temperature (stress), duration and electrolyte leakage (strain) was studied with thebranches of tangerine (Cirrus seticulata, var, Miyakawa). The following relationships were found: (i) therelationship between strain and duration was a hyperbolic curve at a fixed stress; (ii) the relationshipbetween strain and stress was an S-shaped curve at a fixed duration; (iii) the natural logarithm of dura-tion was negatively correlated with the stress as the same strain of plant resulted. Therefore, a mathe-matical model was established to cover these relationships, and the significances of its parameters in plantresistance were discussed. The description of plant resistance by semilethal temperature seems less informa-tive than these parameters. The application of “stress concept ” in physics to the research of plant resistance has been acceptedwidely. However, a useful mathematical model is still wanting.. In this paper the quantitative relationshipamong the freezing temperature (stress), duration and electrolyte leakage ) was studied with thebranches of tangerine (Cirrus seticulata, var, Miyakawa). The following relationships were found: (i) therelationshipbetween strain and durationwas a hyperbolic curve ata fixed stress; (ii) the relationshipbetween strain and stresswas an S (iii) the natural logarithm of dura-tion was negatively correlated with the stress as the same strain of plant resulted. Therefore, a mathe-matical model was established to cover these relationships, and the significances of its parameters in plantresistance were discussed. The description of plant resistance by semilethal temperature seems less informa-tive than these parameters.