In this study, a plug experiment was carried out to study the effects of different portions of vermicompost to substitute peat on apple seedling growth in order to provide a theoretical reference for the application of vermicompost in plug seedling production, especially in horticultural. The designed treatments include: traditional cultural substrate composed with peat (CK), a quarter of peat replaced by vermicompost (T1), a half of peat replaced by vermicompost (T2), and peat totally replaced by vermicompost (T3). Plant height, stem diameter, leaf photosynthetic pigment content, strong seedling index, root morphology and activity of apple seedlings were measured and compared. The results showed that compared with CK, different ratios of vermicompost could significantly promote above-ground biomass of apple seedlings; survival rate of apple seedlings was increased by 15% under T3, reached the maximum; root length, surface area, volume, number, dry weight and activity were increased by 23.40%, 47.61%, 5.88%, 38.57%, 20.17% and 228.75%, respectively. Thereby, vermicompost could fully replace peat and be used as nursery substrates of apple seedlings. The application of vermicompost can not only reduce the cost, but also promote the cycle and transformation of agricultural wastes and reduce the environmental risks.