The invention relates to an electric and thermal combined aging test method and system of a large power thyristor. The method comprises that test data processed by group is obtained according to a thyristor electric and thermal combined aging test; relation between the service life and influential factors of the thyristor under a constant stress is calculated according to the test data processed by group; and influential factors of the service life of the thyristor under the single constant stress are determined according to the relation. Thus, influence of certain factor on the service life of the thyristor can be obtained from a test result, the service life of the thyristor is evaluated, the thyristor as key component can be more reliable, the service life of a converter valve can be optimized and designed, safe and reliable operation of the converter valve is ensured, the using requirement for increasingly large power transmission capacity can be met, and the engineering application value is high.