Abstract: The unreported nine camphene aldehyde O-substituted oximes (2a-2i) were synthesized by nucleophilic substitution reaction using 2-(3, 3-dimethyl bicyclic2.2.1hept-2-ylidene)acetaldehyde oxime and halide as raw materials. They were 2-(3, 3-dimethyl bicyclic2.2.1 hept-2-ylidene) acetaldehyde O-benzyloxime (2a), 2-(3, 3-dimethyl bicyclic2.2.1 hept-2-ylidene) acetaldehyde O-butyloxime (2b), 2-(3, 3-dimethyl bicyclic2.2.1 hept-2-ylidene) acetaldehyde O-(4-chlorobutyl)oxime (2c), 2-(3, 3-dimethyl bicyclic2.2.1 hept-2-ylidene) acetaldehyde O-(3-bro minebenzyl) oxime (2d), 2-(3, 3-dimethyl bicyclic2.2.1 hept-2-ylidene) acetaldehyde O-(4-tert-butyl benzyl) oxime (2e), 2-(3, 3-dimethyl bicyclic2.2.1 hept-2-ylidene) acetaldehyde O-(4-chlorobenzyl) oxime (2f), 2-(3, 3-dimethyl bicyclic2.2.1 hept-2-ylidene) acetaldehyde O-(4-cyanobenzyl) oxime (2g), 2-(3, 3-dimethyl bicyclic2.2.1 hept-2-ylidene) acetaldehyde O-(2, 6-dichlorobenzyl) oxime (2h), 2-(3, 3-dimethyl bicyclic2.2.1 hept-2-ylidene) acetaldehyde O-(ortho-fluorbenzyl) oxime (2i). These products were characterized by FT-IR, GC-MS, ¹H NMR and ¹³C NMR. Taking 2a as an example, the effects of types of solvent, quantity of tetrabutylammonium bromide and benzyl chloride, reaction temperature and reaction time on reaction rate and yield of the product 2a were discussed. The optimum condition were obtained as follows:Methylbenzene as solvent, n(camphene aldoxime):n(benzyl chloride):n(tetrabutylammonium bromide)=1.0:1.8:0.08, the reaction temperature was 60℃, the reaction time was 20 h. Under these conditions, the yield of 2a was 84.1%. The inhibitory effects of compounds 2a-2i on HepG2 cells and MCF7 cells were studied by in vitro antitumor activity tests. The results showed that compound 2b had good inhibitory effect on HepG2 cells, and its IC₅₀ value was 36.3 μmol/L. Compounds 2d, 2h and 2i had inhibitory effects on human MCF7 cells, especially compound 2h, with IC₅₀ of 19.2 μmol/L.