In this article, we study the visible light communication system based on light-emitting diode(LED)indicator. In the transmitter, we employ the hard drive indicator of an embedded personal computer to build a hardware experimental platform. We statistically collect and analyze data to obtain the parameters of the signal model. In the receiver, we employ the single-photon avalanche diode (SPAD) as the receiver to improve the sensitivity of the receiver and extend the communication distance of the system. To solve the problem of clock drift, we propose a pulse width long-short keying (PWLSK) modulation scheme to replace the traditional on-off keying (OOK) scheme; we verify the scheme by hardware experiments. The experimental results show that under the experimental conditions, the bit error rate (BER) of the OOK modulation scheme can not be reduced to below 10 ^-4, which is difficult to meet the communication requirements. Additionally, simulation experiments show that the OOK modulation is more sensitive to ambient light intensity, and can be reduced to 10 ^-5 only when the ambient light intensity is less than 1 lx, while PWLSK modulation scheme can reduce its BER in complex environments with higher ambient light intensity. Based on the above analysis, the proposed scheme can realize the transmission of instant message, file, or voice signal.