[Aim] The effects of Spermacoce alata on the characteristics and species diversity of weed community in the litchi orchards were studied for its potential application in orchards.[Method] A weed community experiment in litchi orchards of the Gaozhou Litchi National Modern Agricultural Industrial Park, Maoming, Guangdong Province, was conducted to assess the effect of S. alata on weed community by comparing weed diversity and height in 90 plots with or without this species.[Result] After the colonization of litchi orchards by S. alata, the number of weeds decreased from 42 in the control plots to 30 in the experimental plots. The weed community structure changed substantially. The importance value (IV) of malignant weeds such as Eleusine indica and Bidens alba decreased, and some weeds, such as Mikania micrantha, Cyperus rotundus, and Polygonum perfoliatum, disappeared. There was a significant negative correlation between weed community height, species diversity indices, and IV of S. alata (P<0.001), which both showed a significant trinomial regression relationship. After the colonization of S. alata in litchi orchards, a weed community with a relatively simple structure and low community height can be established.[Conclusion] S. alata is expected to become a useful Rubiaceae species that can be grown in litchi orchards.