Abstract: Being treated by ultradrying and other artificial aging measures, the physiological and biochemical indexes including seed germination percentage, vigor index, conductivity etc. were determined to study the deterioration process of Pseudolarix amabilis seeds. The results indicated that the germination rate and the seed vigor were not impacted when the seed moisture content declined to 4.2% by ultradrying treatment with silicone at room temperature, while these two indexes would drop obviously and the seeds would be hurt severely when the seed moisture content declined to 3.3%. During the course of artificial aging, the seed conductivity did not increase much when the moisture content was between 4.2%-6.4%, whereas the O2·- content was significantly lower than that of measured with other moisture content. MDA content of the seeds with 4.2%-7.5% of moisture content was significantly lower than that of the seeds which were not treated by ultradrying measures. Seeds with higher moisture content had higher antioxidase activity and a larger variation amplitude during the artificial aging course before imbibition germination.