The invention discloses a vertical-cavity surface-emitting laser which comprises a substrate, a first Bragg reflector, a first limiting layer, an active region, a second limiting layer, a second Bragg reflector and an Ohmic contact layer which are arranged in a laminated manner, wherein the active region adopts a quantum well structure, a potential barrier layer is made of InGaAlAs, and a potential well layer is made of InGaAsN; a heavily-doped tunnel junction and a third limiting layer are also arranged between the second limiting layer and the second Bragg reflector; an oxidized limiting layer is also arranged in the second limiting layer. The invention also provides a preparation method of the laser. The laser has the advantages that the laser uses an InGaAsN / InGaAlAs material system as the active region, has large conduction band order ratio and can effectively limit injected carriers, so that the threshold current is reduced, and the laser gain is improved; on an isometric wavelength band of 1550 nm, the content of N required by an active region material is lower, and devices with high material quality are easy to obtain.