The interaction between polychromatic fields and atoms is an important subject in quantum optics. Frequency locking for small frequency interval multi-field is usually required in some experiments. In this letter, we experimentally demonstrate a holistic scheme for bichromatic laser frequency stabilization. Compared with traditional saturation absorption methods and complicated frequency shift schemes, offset locking for bichromatic fields is simply achieved using polarization spectroscopy and Doppler effect. Frequency locking with a wide-range asymmetry of the detuning is also shown. Our scheme makes laser spectroscopy experiments with polychromatic fields more convenient.