In order to establish the system of high frequency plant regeneration for japonica rice mature embry-os, effects of different concentrations of CuSO₄ and Uniconazole on in vitro culture of mature embryos were studiedusing two rice cultivars of Kongyu 131 and Dongnong 425. The results showed that callus induction and plantlet dif-ferentiation rate of japonica rice mature embryos were apparently improved on the medium with 15.0 μmol/L CuSO₄ or 0.50 mg/L Uniconazole. When 20.0 μmol/L CuSO₄ and 1.00 mg/L Uniconazole were added simultaneously in theinduction and differentiation medium,the callus induction and plantlet differentiation rate of Kongyu 131 was thehighest.When the concentration of CuSO₄ was 10.0 μmol/L and concentration of Uniconazole was 1.00 mg/L, the cal-lus induction rate of Dongnong 425 was the highest. For the plantlet differentiation rate of Dongnong 425, the idealconcentrations of CuSO₄ and Uniconazole were 15.0 μmol/L and 1.00 mg/L.