The invention relates to a high-precision multi-frequency phase-synchronized laser distance measurement device and method, relates to the technical filed of laser measurement, and mainly relates to a phase laser distance measurement technology. In the invention, the problem that a device and a method capable of realizing both synchronization and stability of multiple measurement gauges are in shortage in the phase laser distance measurement technology is solved. The high-precision multi-frequency phase-synchronized laser distance measurement device comprises a dual-longitudinal-mode frequencystabilization He-Ne laser, a multi measurement gauge generation unit, a beam expanding collimating mirror group, a measuring light path and circuit unit and a control casing unit. The high-precision multi-frequency phase-synchronized laser distance measurement method specifically comprises the following steps of: 1, starting the dual-longitudinal-mode frequency stabilization He-Ne laser; 2, taking one beam of laser as a reference laser beam and the other beam as a measurement laser beam; 3, taking [(f'+f2)-(f+f1)] as the frequency of an accurate measurement gauge and taking (f1-f2) as the frequency of a coarse measurement gauge; 4, moving a measurement corner-cube prism to a target end; 5, obtaining a phase difference phi p; 6, obtaining a phase difference phi c; and 7, obtaining the distance. Thus, the method and device disclosed by the invention can be used for laser distance measurement.