The unconditional security of quantum key distribution protocols is based on the assumption of ideal quantum devices, classical devices and random numbers. However, there are some differences between the actual system and the ideal protocol, which may be controlled by the eavesdropper to attack the practical quantum key distribution system. The realistic beam splitter has a wavelength-dependent property, which can be exploited by the eavesdropper to control the measurement basis selection. By proposing the randomness deviation parameters about the measurement basis selection, the wavelength-dependent property can be effectively estimated. More precisely, security of quantum key distribution with wavelength attack is analyzed by utilizing the entanglement distillation and purification technology, and the security key rate is given with different randomness deviation parameters.