The invention discloses a combined trapezoid spray tray. The combined trapezoid spray tray comprises a tray body as well as a plurality of sieve holes and a plurality of float valve structures arranged on the tray body, wherein each float valve structure comprises a valve hole formed in the tray body, an inverted conical barrel nested in the valve hole and fixedly connected with the tray body, a support fixed on the tray body, a support rod connected with the support and inserted into the inverted conical barrel and a float piece arranged on the support rod in a sleeving manner, and the upper edge of the inverted conical barrel is higher than the surface of the tray surface. The combined trapezoid spray tray is high in mass transfer efficiency and high in flux. The invention further provides a plate column.