A rate equation model of multi-quantum wells and multi-active regions were presented. The effects of photon density and the carrier capture-escape-tunnel time on the frequency response of single active region vertical-cavity surface-emitting Laser （VCSEL） and tunnel-regenerated VCSEL with two active regions were simulated by the small signal analysis. The result of simulation shows that the modulate bandwidth of tunnel-regenerated VCSEL with two active regions is larger than that with single active region under the same drive current, then its causes are discussed. Moreover, we simulate the frequency response of the parasitic circuit of tunnel-regenerated internal-contact oxide-confined VCSEL with two active regions after analyzing its parasitic parameters.