In our study, a communication experiment with a 13-km horizontal urban link was conducted based on space diversity technology to examine the communication performance and scintillation effect of this link. Four different distribution models, including the Gamma–Gamma distribution model, were selected. Although the scope of application of the other distribution models was smaller than that of the Gamma–Gamma distribution model, they had better fitting effects than the Gamma–Gamma distribution model did regarding the use of space diversity technology in extreme urban environments with strong or weak turbulence; the degree of fit could reach more than 0.9. We concluded that the space diversity technology had a certain influence on the probability density function of the light intensity fluctuation and a significant inhibitory effect on the scintillation light intensity, resulting in a gain of more than an order of magnitude for the bit error rate.