Circuit model of solarcell is the core section of photovoltaic power generation system simulation model. The modeling methods of flexible amorphous silicon solar cell were studied based on improved photovoltaic cell circuit model. A group of flexible amorphous silicon solar cell’ I–V and P–V data were testedunder the condition of standard solar light. After that, Quasi-Newton method and self-organizing migrating algorithm (SOMA) were adopted to calculate the 8 unknown parameters of circuit model, finally establishing the single diode circuit model of this kind of amorphous silicon thin film solar cell. The optimal results calculated by-self-organizing migrating algorithm showed that the standard deviation of the calculated current in the circuit model is less than 0.79%, while the sum of squared residuals is only 0.05%. The model laid a theoretical foundation of performance optimization and maximum power tracking control technology development of flexible amorphous silicon solar cells.