A multiband low noise amplifier (MBLNA) based on high performance tunable active inductor (TAI) was studied. At amplifier stage, the frequency selection network was constructed by the TAIs with tunable inductance and Q value, and by the variodes with tunable capacitance. It could selectively amplify the signals in different frequency bands in conjunction with common-emitter common-base amplifier circuit. At input stage, the common-emitter amplifier circuit with input inductor in series and emitter inductor negative feedback was employed to realize the broadband input matching. At output stage, the common-emitter amplifier circuit was used to meet output matching and high gain of MBLNA. Furthermore, the current reuse of output stage and amplifier stage reduced power consumption of LNA. Based on WIN 0.2 μm GaAs HBT process library, the performance of MBLNA was verified by ADS. The results indicated that the MBLNA could operate at 1.9 GHz, 2.4 GHz, 3.4 GHz and 5.2 GHz, the voltage gain S21 at above bands reached 27.2 dB, 25.5 dB, 21.6 dB and 17.4 dB respectively, the noise figures (NF) were in the range of 1.3 dB~5.2 dB, the good input and output matching was achieved, and the power consumption was only 17.5 mW.