A current – voltage (I-V) curve is a graphical representation of the relationship between the voltage applied across a solar cell and the current flowing through the solar cell. Key properties of solar cells can also be extracted from the shape and details of the curve, enabling greater insight into its solar energy conversion ability and efficiency. The work focuses on the uncertain I-V curves classification from a big online database based on the current and voltage evaluation. The open-circuit voltage, short-circuit current, current and voltage at MPP on the I-V curves are derived to define the ratios according to the characteristic information of curve shapes. Then, the real I-V curves were acquired from the measurement system and used to verify the proposed method. The results show the proposed method achieved good effects of identifying the curves types and it can be used to meet data requirements of further scientific research.