Research was conducted on the composition, density and diversity indices of soil nematode communities to evaluate biodiversity and effect of Meloidogyne sp on the dragon plant cultivation in Ham Thuan Bac district, Binh Thuan province. The study shows that there are 32 genera belonging to 22 families, 8 orders of phylum nematode in this area. In which, the family Cephalobidae showed highest percentage (43.01 percent), followed by Rhabditidae (16.52 percent), Hoplolaimidae (11.5 percent) remaining families indicated percentage of the nematode communities ( 8 percent). In the qualitative experiment, the families represent high abundance and frequency for free living nematode. In particular, 33.03 percent plant paracitic nematodes, 66.91 percent free living nematode and 0.06 percent predator nematodes were calculated. In addition, Eucephalobus sp. were found positively (22.6 percent) in all samples of soil collected in the study area. Most of the collected root samples, the nematodes caused root-knot at low levels (the infection index level 1). Diversity indices such as Margalef index (d) is quite low, and Hills N2 index are quite high, however these indices are considerably different among sampling stations. The results of the study indicate that the biodiversity of the soil nematodes is medium level.