The invention relates to the field of fingerprint identification and discloses a fingerprint identification sensor. In the fingerprint identification sensor, an auxiliary operational amplifier is connected to a grid electrode of a common-source common-grid structure MOS tube, so that when source-drain voltage of the common-source common-grid structure MOS tube is reduced, gain of the whole fingerprint identification sensor can be still kept high by utilizing the gain amplification effect of the auxiliary operational amplifier, quick gain drop of the whole fingerprint identification sensor, caused by gain drop of the common-source common-grid structure MOS tube, is avoided, and a closed-loop input-output range is widened, namely the linearity degree is improved. When the induction array linearity degree of the fingerprint identification sensor is high, effective signal amplitude of the fingerprint identification sensor can be improved, accordingly the noise influence on signals is reduced, the signal to noise ratio is improved, and finally high sensitivity is achieved.