Considering the air pressure, temperature, ozone concentration and turbulence vertical distribution of scattering communication link in the upper-air, a ultraviolet multipath scattering ling model is modified, combined with Rayleigh scattering theory. The scattering volume is divorced into scattering elements and each element corresponds to every path. Signal strengths of each beams of laser divorced according to different paths are computed respectively. The probability density districutions of each non-line-of-sight signal strengths are calculated by logarithm-normal distribution and non-line-of-sight link turbulence model. Finally, total signal strength probability densities of each path signal in receiving terminal and the link losses are got by the way of each probability density convolutions. According to the factual atmosphere environment, the results show that the newly built probability density distribution is more concentrated. The differential distinction between extinction coefficient and absorption coefficient vertical distribution functions lies 15 km, due to the great impact of ozone absorption. At the range from 2 km to 14 km in the upper-air, scintillation index is higher with transmitter and receiver at the height of 11 km, while it is the lowest with transmitter and receiver at the height of 6 km. Considering turbulence and path loss, transmitter and receiver can be set below 10 km in the upper-air when ultraviolet communication is used in high atmosphere.