为了解决可见光通信发射系统中光信号直接加载到白光LED的驱动电路上产生的驱动电流不稳定、不可预测的噪声、灯光闪烁的问题，提出了一种应用在可见光通信发射系统中的双调制方法。内部调制采用PWM载波编码调制，解决灯光闪烁问题，外部调制采用一个由铌酸锂材料制成的调制外壳，解决了驱动电流不稳定，噪声的问题。实验表明，这种双调制方法具有实践价值。“,”To solve the problem of instability of the drive current,uncertain noise and light flashing,which are generated by the optical signal directly being uploaded in the drive circuit of white light LED in launch system of visible light communication,a double modulation method was proposed. internal modulation adopted PWM carrier encoding modulation solve the problem of light flashing. external modulation adopted a modulation shell which is made of Lithium Niobate materials to solve the problem of instability of drive current and uncertain noise. Experimental results show that this double modulation method has practical value.