The tuning characteristics of widely tunable wavelength vertical-cavity surface-emitting lasers (VCSELs) have been investigated based on transfer matrix model and finite-element structure-electric coupled-field analysis model and experiment, in which the electrostatic tuning of wavelength and microelectronic mechanical system (MEMS) cantilever of the tunable VCSELs with central wavelength 980nm were designed. The analysis shows that the characteristics of wavelength tuning of VCSELs will be affected by the maximal displacement of cantilever and the structure of wavelength resonator. The tuning range can be improved based on the optimization of sacrificial layer for a given geometry of cantilever and active region of the device. In this paper, the structure of tunable VCSEL is designed. Further numerical simulations show that a continuous tuning range up to 32nm is obtainable, tuning efficiency is 0.12, and the whole tuning range of wavelength lies within the high gain region of the InGaAs quantum wells with GaAs barrier.