The invention provides a gas detecting apparatus used in production of Shangtang orange plants. The gas detecting apparatus comprises a gas absorption port and a gas detection device, wherein the gasdetection device is rotatably connected with an upper spiral port through a lower spiral port; the upper end of the upper spiral port is provided with the gas absorption port; the upper end of a large-particle filter screen is arranged on the upper end of the inner side of the gas absorption port; a small-particle filter screen is arranged on the lower end of the large-particle filter screen; a rope hanging mouth is formed in the right upper end of the gas detection device; a smoke detector is arranged on the upper end of the gas detection device; a sensor is mounted on the lower end of the smoke detector; a display screen is arranged on the lower end of the sensor; a switch control panel is arranged on the lower end of the display screen; and a power switch is arranged on the middle partof the switch control panel. Large and small particles in gas can be filtered out through the gas absorption port, so an instrument is allowed to have prolonged service life. The gas detecting apparatus provided by the invention can sensitively detect gas and is convenient to use.