The invention relates to distributed photovoltaic power optimizers and a control method. When series connection and parallel connection of photovoltaic modules are mismatched due to factors such as partial or intermittent shielding or aging of photovoltaic arrays, the control method is more obvious in effect. The control method is characterized in that after directly attached to photovoltaic modules, the power optimizers are connected through a series connection framework, and the power optimizers in the series connection framework firstly obtain voltage signals and current signals of the photovoltaic modules connected with the power optimizers and directly perform maximum power tracking on the single module, so that the photovoltaic modules output maximum power, and results are transmitted to a central controller. The central controller receives the maximum power calculated by each optimizer, voltage and current conditions of the shielded modules are monitored, and the voltage and current output by all the modules are coordinated through calculation. The control method not only can ensure that each photovoltaic module works at an optimal working point, but also can enable setting of bus voltage to be more flexible and stable, and the system can serve as a direct-current power supply and also be used for an independent or grid-connection photovoltaic system.