An analysis has been carried out to evaluate the Signal to Noise Ratio (SNR) and average bit error rate (BER) in presence of pointing error and atmospheric turbulence. The probability density function (pdf) of atmospheric turbulence and pointing error has been combined to find out the joint effect on the BER performance on Free-Space Optical (FSO) system. The average BER is evaluated over the combined pdf of atmospheric turbulence and pointing error.The BER performance results are numerically evaluated for several values of pointing error and different link length using Binary Phase Shift Keying (BPSK) subcarrier intensity modulation. For strong turbulence power penalty is around 20dB, while for strong jitter power penalty is around 30dB at a BER of 10 -9 and bit rate of 1 Gbps.