Taking tomato cultivar‘ Shijia101’（ highly susceptible to root-knot nematode） and ‘Jingxuanhongtao’（middle resistant to root-knot nematode） as experimental material， this paper studied the effect of root-knot nematode （Meloidogyne incognita） infection on leaf blade chlorophyll content and fluorescence parameters of different tomato （Solanum lycopersicum L.） varieties， by pot cultivation in greenhouse and artificial inoculation at seedling stage. The result indicated that nematode infection led the leaf blade chlorophyll content reduced， the maximal photochemical efficiency（ Fv/Fm） and actual photochemical efficiency（ ΦPS Ⅱ）were all reduced. Whereas the non-photochemical quenching coefficient（ NPQ） was firstly increased， then
declined. There were remarkable differences among varieties with different resistances. Among them， the decline range in chlorophyll content， Fv/Fm and ΦPS Ⅱ of‘ Shijia101’ was bigger than that of‘ Jingxuanhongtao’.There were significant differences in NPQ of these 2 varieties， 10 days after infection. The increasing range of ‘Jingxuanhongtao’ was remarkably bigger than that of‘ Shijia101’. Obviously， the effect of nematode infection on leaf blade of‘ Jingxuanhongtao’ was smaller than‘ Shijia101’. The chlorophyll fluorescence parameters，Fv/Fm， ΦPS Ⅱ and NPQ can be the physical reference indexes for identifying tomato varieties with resistance to root-knot nematode， and the parameter NPQ is the most suitable one.