In order to investigate the enrichment characteristics of heavy metals in soil of different urban-rural environmental gradient zones in Haikou, agricultural surface soil samples were collected from four different urban-rural environmental gradient zones in Haikou, including the urban center, urban-rural transitional zone, rural area, and natural area. The concentration of eight heavy metals were measured, including Cd, Hg, As, Pb, Cr, Cu, Ni, Zn. The enrichment characteristics of heavy metals in soil of Haikou were analyzed through the vertical distribution and migration characteristics of heavy metals, the correlation between heavy metals and physicochemical indicators, and the enrichment coefficient of heavy metals. The results showed that the average contentration of Cd, Pb, and Zn in surface soil was higher than that in deep soil, and heavy metals had varying degrees of cumulative effects. There was a significant positive correlation between soil pH and Cd content, and soil pH had a significant impact on the degree of Cd heavy metal enrichment. Soil organic matter (SOM) was positively correlated with the content of Hg, Cr, Cu, Zn, and Ni. The correlation between layer A and layer B was stronger than that of layer C. Surface soil SOM had a significant impact on heavy metal enrichment. The proportion of sites with heavy metal enrichment coefficients greater than 1.2 ranged from high to low was Cd (70.0%), Hg (41.7%), As (36.7%), Pb (28.3%), Zn (21.7%), Cu (18.3%), Ni (18.3%), and Cr (15.0%). The enrichment degree of heavy metals in agricultural land soil in Haikou showed a certain distance gradient variation feature, with the increase of distance from the urban center, the enrichment degree of eight soil heavy metals showed a gradually decreasing trend. Only Cd showed enrichment in the natural area, and no enrichment points were found for the other 7 heavy metals. The enrichment coefficients of Cd, Hg, and As soil heavy metals involved a wide range. The points with enrichment coefficients greater than 8 for Cd in urban central areas far exceeded that in urban-rural and rural areas. The points with enrichment coefficients greater than 2 for Hg were only located in urban central areas and urban-rural transitional areas. The proportion of points with Cd enrichment coefficients greater than 1.2 far exceeded the other seven heavy metal projects. The coverage of Cd enrichment in urban and rural environmental gradients was the highest, and the regional enrichment characteristics were obvious. In addition, the enrichment coefficient of 30% Cd points was greater than 4, indicating a strong soil Cd enrichment degree, which should be paid attention to.