Charge exchange recombination spectroscopic (CXRS) diagnosis is a routine diagnostic method for the measurement of the temperature and the rotation velocity distribution of ions on nuclear fusion devices. The completely ionized carbon ion C6+ in plasma exchanges charge with high power neutral deuterium and radiates the carbon line (C VI, 529.059 nm, n=8→7). By measuring the Doppler shift of C VI, the velocity of C6+ can be calculated. Precise wavelength calibration is a precondition for the accurate measurement of the velocity. The off-line and on-line wavelength calibration methods for the CXRS system on EAST (experimental advanced superconducting tokamak) device are introduced. The advantages and disadvantages of both methods are discussed in detail. Considering the special condition of the EAST plasma and the current situation of the CXRS diagnosis, an on-line calibration method using laser (wavelength 532.1 nm) is proposed. Simulations and experiments are performed for the calibration method and the results are consistent with those obtained via the commonly used calibration lamp.