Abstract: Phosphorus (P) is a key factor of acid soils to forests growth.The variations of P in fire slash were vital to regeneration and seedling growth.The results showed a large increase of P in surface soil immediately after burning.Especially available P in the S 0~5cm, 5~10cm and 10~15cm soil layers of serious fire slash (S) was 33 times, 64.5 times and 12.5 times higher respectively than those in control soils, and this depended upon fire intensity.The results also showed that as time went on the amount of increased P declined.