The hydro-priming technique was adopted for Pinus tabulaeformis seeds to solve the poor emergence and drought resistance of direct seeding in the present study. The effect of hydro-priming on the seed, seedling, and the drought resistance mechanism of the primed seedling were also explored. The results showed that the optimal condition for hydro-priming was at 10 °C for 10 days under dark condition, and in the presence of 30% additional water to the original seed mass. Specifically, a succession of total water percentages (53.6%, 14.5%, 14.5%, 8.3%, 5.7%, and 3.4%)was added at 0 h, 8 h, 16 h, 40 h, 64 h, and 88 h after starting priming, respectively. The effects of hydro-priming on P. tabulaeformis seeds were documented in comparison to the control. First, the 50% seed germination days and hard seed rate of primed seeds were significantly reduced by 37.5% and 48.8%, respectively. The germination index, the final germination percentage, and seed vitality index were also improved by 42.8%, 18.2%, and 16.8%, respectively. Soluble sugar and soluble protein content of primed seeds increased by 25.2% and 18.0%, respectively. These results demonstrated that the hydro-priming technique improved the performance of P. tabulaeformis seeds. Second, the relative plant height of hydro-primed seedlings decreased by 34.7%. Stem diameter, fresh seedling weight, and root length increased by 30.9%, 105.4%, and 3.9%, respectively. Third, catalase and peroxidase activity in seedlings and the dehydrogenation enzyme in the root increased by 31.2%, 9.4 times, and 70.6%, respectively. Free amino acid content declined by 41.4%. These results show that the physiological indexes of hydro-primed seedlings were considerably different to those of non-primed, with hydro-priming strengthening P. tabulaeformis seedlings. Finally, under drought stress, proline and soluble sugar content in seedlings from primed seeds were significantly enhanced by 39.6% and 118.9%, respectively. In contrast, malondialdehyde content significantly decreased by 93.4%. The results indicate that the increased soluble sugar and soluble protein content in hydro-primed seeds greatly enhances seed germination and seed germination rates. On the other hand, the function of the seedling antioxidant system requires further improvement by increasing seedling antioxidase activity and decreasing malondialdehyde content, which significantly enhance seedling drought resistance.