The invention relates to a hands-free call 
system which comprises a singlechip 
microcomputer control module, a power supply module, a hands-free switching module, a sound effect 
processing module, a power amplification module, a volume detection module, a 
signal processing module, a 
loudspeaker adjustment module and a 
Bluetooth module, wherein the power supply module, the hands-free switching module, the sound effect 
processing module, the power amplification module, the volume detection module, the 
signal processing module, the 
loudspeaker adjustment module and the 
Bluetooth module are all connected with the singlechip 
microcomputer control module. The hands-free call 
system has the beneficial effects that due to the cooperative action of the volume detection module, the 
signal processing module and the 
loudspeaker adjustment module, the hands-free call 
system disclosed by the invention can automatically adjust the magnitude of an output volume according to the magnitude of 
environmental noise, and is more energy-saving; by the additional arrangement of the 
Bluetooth module, the hands-free call system can support 
Bluetooth communication; and meanwhile, a WIFI module is convenient for 
data transmission. During use, the hands-free call system can eliminate echo of an 
audio signal.