In order to study the transmission characteristics of blue-green laser across the the air-sea cross-medium, the downlink transmission model of blue-green laser through the sea surface-bubble layer is developed based on Kirchhoff approximation, Mie theory, and Beer theory for the air-sea cross-medium interface and the the subsurface bubble layer. The factors such as the fluctuation of sea surface height affected by wind speed, the change of bubble concentration in seawater, the mixing of clean bubbles and thin film-covered bubbles in seawater are fully considered. The relationship among the transmittance of blue-green laser passing through the sea surface-bubble layer, wind speed, the transmission depth in seawater, and the angle between receiving plane and transmitting plane is calculated numerically. The results show that the transmittance of the blue-green laser passing through the air-sea interface and the seawater mainly depends on the wind speed and the laser transmission depth in the seawater. With the increase of wind speed, the sea surface roughness and the concentration of bubbles in the upper ocean increase, and the laser transmittance decreases. Compared with seawater, the effect of bubble layer on laser transmittance decreases with the increase of depth. For bubbles with radii greater than 10 μm, the covering of the protein film has little effect on the attenuation of the blue-green laser.