df = pd.DataFrame(columns=['col1', 'col2'])
df = df.append(pd.Series(['a', 'b'], index=['col1', 'col2']), ignore_index=True
    )
df = df.append(pd.Series(['d', 'e'], index=['col1', 'col2']), ignore_index=True
    )
df
Appending a list or series to a pandas DataFrame as a row?