In traditional two-stage grid-connected photovoltaic (PV) generation systems, the front-end DC/DC stage typically employs a single Boost circuit with Maximum Power Point Tracking (MPPT) algorithm to operate the PV cells at the maximum power point. This often results in significant current ripple on the circuit inductor, necessitating large-value inductors and input-side capacitors, which is detrimental to system stability and economy. This paper proposes a two-stage PV system based on a multiphase Boost-MPPT approach. The front-end of this system enables the PV array to rapidly track and stabilize at the maximum power point while achieving current sharing among the inductors of each Boost phase, thereby effectively reducing input current ripple. The rear-end DC/AC stage utilizes a three-level inverter topology with a four-wire dual-loop control strategy to achieve grid connection. The studied multiphase Boost-MPPT based PV generation system demonstrates significantly reduced grid current harmonics compared to traditional two-level PV systems, making it more suitable for practical applications. Finally, a simulation platform was built and an experimental prototype was developed based on the above principles, validating the conclusions.