Deep bed solar drying experiments were conducted for alfalfa. An indirect forced convection solar dryer which consists of a solar air heater, a drying tower, an electric fan and a measurement system was used in the experiments. Hot air that heated by solar heater was forced through the forage by an electric fan. In order to examine the effect of drying element on the deep bed drying of alfalfa, the forage has been set into three layers, each layer was 1.2m high, and drying experiment was performed in the drying tower at the meantime. Result showed that the drying temperature in real-time solar drying was affected by the weather elements, and the temperature of alfalfa was affected by the air temperature, humidity and the position of alfalfa in bed. Along the air flow, the temperature of the alfalfa which located near inlet point was higher than the one away from the inlet in the further place. And the moisture content of alfalfa and its drying rate were affected by the air temperature, humidity and the position of alfalfa in the bed. The drying rate of alfalfa was various based on its different position in the drying bed. It is more effective in high temperature and low humidity for deep bed wet alfalfa.