Soundscape design in city parks is important for a better visiting experience. The aim of this research is to find a more effective way to design soundscapes in city parks, by exploring the relationships between certain physical and psychoacoustic parameters and soundscape composition parameters as proposed in this study, including perceived loudness of individual sound (PLS), perceived occurrences of individual sound (POS), and soundscape diversity index(SDI). The parameters were based on soundscape information gathered with a specifically designed soundwalk method in five city parks in Xiamen, China. The results showed that the soundscape composition parameters play important roles as soundscape parameters. LCeq–LAeq, LA10–LA90 and sharpness showed more explanatory power to the soundscape composition parameters of individual sound categories than other physical and psychoacoustic parameters. PLS of human sounds was the most frequently introduced variable for nearly all the other objective parameters, followed by SDI. Some of the soundscape composition parameters were found to be mutually explainable, including PLS of human sounds with LA10, LCeq–LAeq and sharpness, respectively, POS of traffic sounds with LA10, and PLS of both mechanical and geophysical sounds with sharpness, which supply important information for soundscape design in city parks.