[Objective] To explore the endangered reasons of Picea mongolica at the seed ecology level in order to provide theoretical references for making the conserve measures of P. mongolica natural forest.[Methods] Seed viability was tested with different habitat storage periods. The responses of seed germination to temperatures and lights were investigated. The tolerance of P. mongolica seed to salinity during seed germination and seedling growth and the responses of seedling emergence to sand burying were studies.[Results] ① The viability of matured P. mongolica seeds was 79%, of which, about 12% seeds suffered from freeze injury and the remaining 67% suffered from the pest nibble and disease harm. The buried seed viability was reduced at a speed of 9.5% every year. ② Germination of P. mongolica seeds was very easy and the germination percentage was more than 40% when the temperature was more than 10℃. The seed germination rate at a dark-light alternation condition was higher than other light conditions, and the optimal sand burial depth for P. mongolica seedling emergence was 0.5 cm as it satisfied the light and temperature requirements of seed germination. The germination characteristics increased the morality as a lot of seeds germinated in desert habitat environments. ③ Seed germination and seedling growth were significant decreased with the increase of NaCl concentration. When NaCl concentration was around 0~100 mmol/L, the germination rate (R_IG) was decreased from 69% to 49%, recovery germination rate (R_GR) was increased from 0 to 6%, and the initial seedling length (L_IS) was reduced from 7.12 to 1.16 cm. The recovery seedling length (L_RS) was increased from 0 to 0.03 cm when the concentration of NaCl was more than 100 mmol/L, the seed germination and seedling growth were completely inhibited(IGR<49%,ISL<1.16 cm) and the ability to recover was poor (R_GR<10%, L_RG<1 cm). Unfortunately, soil salinity contents over 100 mmol/L were widely distributed in the natural habitat of P. mongolica. ④ Seedling emergence was significantly decreased with the increase of sand burial depths. The emergence rate reached 69% with the 0.5 cm sand burial depths and reduced to 8.5% with the 2.0 cm sand burial depths. The habitat of P. mongolica with sand burial depths over 2.0 cm was widely distributed, thus the seedling emergence was less than 8.5%. The P. mongolica seedling was continuously suffered from the pest nibble, disease harm, salinity and moisture stress, freeze injury and interspecific competition.[Conclusion] The main endangered causes of P. mongolica were the serious diseases and pests, low seed viability in habitat soil seed banks, the low survival rate of seedlings and badly environments in habitats.