Abstract: Abstract: The black soil area of Songnen Plain is an important corn production area in China. The area of continuous corn cropping is large, and a large amount of straw is left over, which causes environmental pollution by burning in the open air. Returning straw to the field is one of the important ways for sustainable development of agriculture. At the same time, straw returning affects the adsorption and fixation of phosphorus in soil, which has a direct impact on the availability of soil phosphorus. In order to explore the effects of straw returning and phosphorus application rate on phosphorus adsorption and desorption characteristics of black soil under the continuous corn cropping in Songnen Plain. A frame culture experiment was initiated in 2016 at Northeast Agricultural University Experimental Station, where corn was continuously planted for three years. A two-factor split-plot design was adopted in this experiment, the main plot was straw returning method with no straw returning (S0), straw burying (S1) and straw burning (S2), and the sub-plot was phosphorus application level with 0 (P0), 34.50 (P1), 69 (P2), 103.50 (P3) kg/hm2 (P2O5). After the corn was harvested in 2018, the 0-20 cm soil layer was collected to determine the adsorption and desorption performance of soil phosphorus and the content of soil available phosphorus. The results showed that: 1) Langmuir isothermal adsorption equation was the most suitable for fitting the adsorption characteristics of phosphorus of black soil. 2) Both straw returning and phosphorus application rate significantly affected the phosphorus adsorption and desorption characteristics of black soil, and the interaction between them was significant. Under the same straw returning method, with the increase of phosphorus application rate, the phosphorus adsorption amount of soil, Qm(maximal P adsorption), K(adsorption affinity constant), MBC(maximum buffer capacity) and SPR(standard phosphorus requirement) decreased gradually, while the RDP(readily desorbable P), DPS(degree of P saturation) and the phosphorus desorption amount and rate of soil increased gradually, with the largest difference under S0 treatment, followed by that under S2 treatment, and the smallest difference under S1 treatment. Under S0 treatment, the average phosphorus adsorption amount of P3 treatment decreased by 10.22% compared with P0 treatment (P<0.05). Under S2 treatment, the average phosphorus adsorption amount of P3 treatment decreased by 4.51% compared with P0 treatment (P<0.05). However, under S1 treatment, there was no significant difference between P3 and P0. Under the same phosphorus application level, compared with S0 treatment, both S1 and S2 could reduce the phosphorus adsorption capacity and increase the phosphorus desorption amount and rate of soil, however there was no significant difference between S1 and S2. Among them, under no phosphorus application (P0), the phosphorus adsorption amount of soil under S1 and S2 treatment decreased the most, which were 6.87% and 5.31% (P<0.05), respectively. Under high phosphorus application (P3), there was no significant difference in the phosphorus adsorption amount of soil under S0, S1 and S2 treatment. 3) The standard phosphorus requirement (SPR) under different phosphorus application treatments ranged from 71.02 to 91.67 kg/hm2, of which the SPR (73.58 kg/hm2) of S1P2 was the closest to the phosphorus application level of P2 (69 kg/hm2), which was the appropriate phosphorus application method of black soil area in Songnen Plain. The purpose of this study is to provide some theoretical basis and reference for the rational application of straw returning and phosphate fertilizer in black soil area.