Because the traditional synchronized phasor algorithm is greatly affected by the intermediate harmonics of the power grid， this paper proposes a synchronized phasor measurement algorithm based on a newly improved matrix bundle. The power grid signal is constructed into a Hankel matrix， which is decomposed into singular values， and the noise interference components are filtered out using an adaptive order determination method. The accurate voltage amplitude， frequency and phase angle are obtained through matrix operation， and the simulation results show that this algorithm is superior to the traditional recursive Fourier transform algorithm in measuring power grid signals containing interharmonic components. A portable power grid synchronous phasor measurement device is designed to solve the problem of large volume and high cost of traditional synchronous phasor measurement equipment. The actual frequency of the crystal oscillator is monitored by high-precision satellite synchronous signal， and the sampling control parameters are dynamically adjusted to reduce the sampling time error. The synchronously sampled power grid waveform parameters and time tags are wirelessly transmitted to mobile terminals to complete the calculation of power grid signal amplitude， frequency and phase angle. The actual test shows that the device has high measurement accuracy， in which the measurement errors of voltage amplitude， frequency and phase angle are 0.038 5%， 0.000 51 Hz and 0.053 7°，respectively， which meets the requirrement of "Test specification for synchrophasor measurement unit for power systems"（GB/T 26862—2011）， and has practical application value.