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Global warming intensifies the change of freeze-thaw pattern in seasonal permafrost areas, and phosphorus (P) is the main limiting element of farmland ecosystem response to climate warming. Based on laboratory experiments, taking three typical soils in Heilongjiang Province: black soil, chernozem and white clay as the research object, and using decomposed straw (F) and biochar (B) as exogenous media, the freeze-thaw cycle test was carried out for a period of 50 times, aiming to evaluate the effects of foreign soil amendments on phosphorus availability of three typical soils in Heilongjiang Province under freeze-thaw cycles. The experimental results showed that the application of foreign media in the three types of soil significantly changed the physical and chemical properties of the soil and increased the availability of soil phosphorus in different degrees during the freeze-thaw cycle. With the increase of freeze-thaw cycles, the Olsen-P content of soil showed a trend of first increasing, then decreasing and then increasing. In black soil, chernozem soil and white clay the treatments with the largest increases were F, F+B and F+B, respectively.Soil pH value, water content, freeze-thaw cycles and acid phosphatase activity were important factors affecting soil Olsen-P content.According to the results of HEDLEY phosphorus classification, the average content of F, F+B and F treated active phosphorus components was the highest in black soil, chernozem and white clay under freeze-thaw cycle. The content of stable P in different active P reservoirs was significantly higher than that of active P and moderately unstable P in the three soils.The research results can provide theoretical reference for the comprehensive utilization of crop straw.