A converting circuit and a communication device are provided. The converting circuit includes: a sample hold circuit for receiving an analog signal; a Digital to Analog Converter (DAC); a comparator being connected with an output end of the sample hold circuit and an output end of the DAC; and a control circuit being connected with an output end of the comparator, wherein when the sample hold circuit receives an analog signal, the control circuit controls the sample hold circuit and the comparator to work, controls an output of the DAC based on an output of the comparator, and outputs a corresponding digital signal; and when the control circuit detects a digital signal is input, the control circuit controls the DAC to convert the digital signal into an corresponding analog signal and output the corresponding analog signal. The converting circuit can reduce chip area and chip cost.