In order to solve the problem that the laser satellite terminal can realize the ranging function while completing the communication function, this paper designs a method based on the Delta-Sigma modulation to realize the laser phase ranging, which can integrate the functions of communication and ranging. Multi-frequency point phase ranging is used to balance ranging range and ranging accuracy. Multi-frequency modulation signals are generated using high-speed digital Input and Output (I/O) ports based on Delta-Sigma modulation without any Digital-to-Analog Converter (DAC). Based on the Delta-Sigma modulation method, multiple frequency points for multi-frequency phase ranging can be generated at the same time, which is better than the traditional method of generating each single frequency point separately. Selecting the high frequency of 187.50 MHz and the low frequency of 1.50 MHz, the ranging accuracy can achieve 1 mm in the range of less than 100 m.