This study clarified the adsorption-desorption characteristics of phosphorus in soils at different slope positions in citrus orchards in the southern hilly region，to provide a scientific basis for differentiated fertilization strategies under various terrain conditions. The experiment selected typical soil samples from the upper and lower slopes of citrus orchards in Chongqing City，Hunan Province，and Guangxi Zhuang Autonomous Region as the subjects of study. Through phosphorus adsorption-desorption experiments，combined with the Langmuir isotherm adsorption equation，characteristics such as the maximum adsorption capacity(Qmax)，adsorption reaction constant(K)，maximum buffering capacity(MBC)，and phosphorus desorption rate(PDR)of phosphorus adsorption in citrus orchard soils at different slope positions were explored. The results showed that:(1)The Langmuir isotherm adsorption equation fitted the phosphorus adsorption by soils at different slope positions in citrus orchards well(R2=0.97-0.99)，with Qmax of the slope soil(1000.9-1829.9 mg·kg-1)being lower than that of the footslope soil(1142.1-2426.9 mg·kg-1). However，the higher K value(0.04-0.776)and MBC(73.2-841.7 mg·kg-1)of the slope soil indicated an advantage in the adsorption efficiency and long-term stability of phosphorus. In contrast，although the footslope soil had a higher Qmax(1142.1-2426.9 mg·kg-1)，its lower K value(0.018-0.398)and MBC(43.7-556.9 mg·kg-1)suggested certain limitations in the long-term stable adsorption and utilization efficiency of phosphorus.(2)Correlation analysis results showed that the K value on the slope was significantly negatively correlated with total phosphorus and available phosphorus，and the MBC was significantly negatively correlated with available phosphorus and positively correlated with free iron oxides；PDR was positively correlated with total potassium. For footslope soil，the K value was negatively correlated with available phosphorus and positively correlated with pH value；MBC was significantly negatively correlated with available phosphorus and PDR；PDR was significantly positively correlated with available phosphorus and total potassium.(3)Redundancy analysis indicated that available phosphorus and complexed aluminum oxide were the main factors affecting phosphorus adsorption-desorption，with contribution rates of 64.8% and 10.1%，respectively(P<0.01). In summary，a moderate deep application strategy should be implemented for slope soil in citrus orchards in the southern hilly region，combined with organic fertilizer to improve phosphorus adsorption efficiency and soil retention capacity，and regular monitoring of soil nutrients to adjust fertilization amounts. For the footslope soil，fertilization amounts should be controlled，using a small and frequent application method，and considering the use of slow-release fertilizers and soil management measures to reduce phosphorus loss and improve utilization efficiency.