Abstract: The secondary Quercus liaotungensis population in Qinling mountains was selected as the experimental object, and the population structure of Quercus liaotungensis and the responses of seedling regeneration to DBH pattern, density pattern and competition pattern were studied by using the relevant methods of spatial pattern analysis. The results showed that: (1) The number of small diameter individuals (DBH <16 cm ) was significantly higher than that of large diameter individuals (DBH ≥16 cm). (2) The average diameter at breast diameter (10.376 cm) around the seedling regeneration position was smaller than the average level of the plot (12.385 cm). (3) The population density of the seedling regeneration position (0.126 plants / m²) was higher than the average level of the plot (0.084 / m²). (4) The competition index of seedling regeneration position was at a moderate level of the plot, and the law was not obvious. The results provided some certain reference value for a deeper understanding of the secondary forest regeneration mechanism.