Japonica rice cv 77170 was transformed with pBI222 carrying hygromycin phosphotransferase gene (hpt) by using biolistic bombardment and fertile transgenic rice plants were obtained. In T1 and most T2 generation the performance of hygromycin resistance was normal. Only in T2 progeny of SG-15 some lines showed decreased resistance. Mendelian inheritance of hygromycin resistance was showed as single dominant locus and proved by Southern blotting analysis in T1 and T2 generation of all transgenic plants. Multiple copies of hpt integrated into rice genome. These copies linked closely and inherited stablly. Msp I digested Southern blotting showed that methylation of hpt existed commonly in transgenic plants and their progeny, therefore uncomplete silencing of hpt in some T2 progeny of SG-15 was not associated with hpt methylation probably.