Abstract: In order to study tumor heterogeneity,two series of clones (strain B,and f) were selected in vitro from the LLC cell line by the single cell cloning technique.Two strains were cultivated largely in vitro and inoculated into the foot pad of the syngeneic C₅₇ BL/6 mice.The tumorigenicity and metastatic ability in strain B were considerable higher than that in strain f.By observating other biological characteristics,it was found that the shape adhersion ability and growing style of cells were different between strains B and f,the lectin reactivity was occured between strain B and lower quantitative ConA,and between strain f and higher quantitative ConA.These results suggested that tumor cell are consist of sub clone of difference in biological characteristics.