This investigation aimed to explore the comprehensive quality characteristics of different parts of Eucommia ulmoides bark and the dominant soil factors affecting its quality. 15-year-old Eucommia ulmoides artificially cultivated in Bozhou District, Zunyi City, Guizhou Province were taken as the research object. Soil samples corresponding to their growth and the bark of Eucommia ulmoides from the upper, middle and lower parts of the tree trunk respectively were collected. Through the detection of soil physical and chemical properties, the contents of effective components (pinoresinol diglucoside, genipin), trace elements (zinc, selenium, nickel, manganese, iron) and heavy metals (cadmium, copper, lead, arsenic, mercury) in different parts of Eucommia ulmoides bark were analyzed, a comprehensive quality evaluation in combination with principal component analysis was conducted, and correlation analysis between soil physical and chemical properties and the quality of Eucommia ulmoides bark was carried out. The results showed that the contents of pinoresinol diglucoside and genipin, from high to low, were in the order of middle part > upper part > lower part. The contents of zinc, nickel and iron from high to low were in the order of upper part > lower part > middle part, and the contents of selenium and manganese from high to low were in the order of lower part > middle part > upper part. The heavy metal content in the bark of Eucommia ulmoides from the three parts did not exceed the standard. Principal component analysis indicated that the comprehensive scores of the upper, middle and lower parts of Eucommia ulmoides bark were 0.813, -0.278 and -0.536 respectively, and the quality of the upper part of Eucommia ulmoides bark was better. Correlation analysis indicated that in the upper part of Eucommia ulmoides bark, the content of resinol diglucoside was negatively correlated with the available phosphorus content in the soil, and the lead content was negatively correlated with the total phosphorus content in the soil. The arsenic content was positively correlated with soil pH, and the mercury content was positively correlated with the available potassium content in the soil. In the middle part of Eucommia ulmoides bark, the arsenic content was negatively correlated with the total phosphorus content of the soil, and the manganese content was negatively correlated with the alkali-hydrolyzable nitrogen content of the soil. The mercury content was positively correlated with soil pH. In the lower part of Eucommia ulmoides bark, the content of genipin was negatively correlated with the total phosphorus content of the soil, the zinc content was negatively correlated with the total nitrogen content of the soil, and the manganese content was negatively correlated with the alkali-hydrolyzable nitrogen content of the soil. The copper content is positively correlated with the available phosphorus content in the soil, and the lead content is positively correlated with the soil pH. In conclusion, the soil fertility for the growth of Eucommia ulmoides in the study area is good, and the quality of the upper part of the Eucommia ulmoides bark is superior. Based on the quality differences of different parts, it is advisable to harvest the Eucommia ulmoides bark by part to improve the efficiency of resource utilization.