A gravity sensing system-controlled parallel speaker assembly applied to a cell phone has the following features. Two earpieces are respectively disposed at both ends of the cell phone, and the two earpieces are connected in parallel and then connected to a signal source. Alternatively, two earpiece assemblies are respectively disposed at both ends of the cell phone, and the two earpiece assemblies are connected in parallel and then connected to the signal source. Further, two switches are controlled by gravity sensing signals, such that the switch having a greater height is closed, and the switch having a smaller height is opened. The earpiece assembly is an assembly formed by connecting an earpiece and a switch in series. The signal source is a prior art terminal that provides an earpiece of a cell phone with electrical signals. The speaker comprises a commonly known earpiece and speaker. In addition, the cell phone comprises one or more prior art conventional cell phone microphones; however, said microphones are disposed at the middle portion of the cell phone. The microphone is connected in parallel. Thus, only the upper earpiece can emit sounds, and sounds from the speaker will not be emitted, and microphone voice reception will not be affected regardless of which of the earpieces is near the ear during a call.