Abstract: A new root-knot nematode disease of the citrus was found in coast sand soil through servey in 1989. At least several couties and one hundred thousand species of citrus was infected. The citrus trees infected by nematodes showed symptoms including yellowing leaves, sparse foliage, small fruits. defoliated branch ends and so on. The pathogen, which is a new species, was named as Meloidogyne dong-haiensis sp. nov. It has more or less round perineal pattern, low dorsal arch. The area around vulva hasa few or no striae cxcept sometimes some short ones which connected with the ends of the vulva slit. Phasmids adjarcet to tail terminus, small but clear. Lateral field not distinct, sometimes marked by irregular cearse or indistinct striae or interruption of the pattern. Still there are some wave striae near inside lateral field. The most characteristic features of the pattern of this species. which differ from other closed species, are that there are some irregular coarse striae which sometimes parallel the other fine striae, sometimes intersect them. Female body pyriform with short neck. The distanoe from excretory pore to the base of the stylet is three times as long as the lenth of the stylet. Male head flattened with rounded edges, lip region not annulated. Second stage juvenle has longer body (420-480μ),rectum undilated.