Taiji-1 is the first demonstrated experimental satellite of Taiji program in China. Phasemeter is one of the key components of the laser interferometer which is responsible for phase extraction of the heterodyne signals. In this paper, we present the architecture and implementation of Taiji-1 phasemeter. The DPLL architecture is used in Taiji-1 which is generally regarded as the best choice for space missions. We test the phasemeter on the ground and the results show that the phasemeter reaches the sensitivity of 600 mu rad/root Hz in the frequency range of 0.01-1 Hz. It is further shown that it can reach the accuracy of 30 mu rad/root Hz in the frequency range of 0.1-1 Hz, both of which are within the technical requirements of Taiji-1 mission.