As for permanent magnet synchronous motor (PMSM) drive systems with dc-bus voltage sensor failure, a non-linear function integral sliding mode(NFISM)-based finite-control-set model predictive current control(FCS MPCC) strategy with sensorless is put forward. In principle, measuring dc-bus volt-age of voltage source inverter is vital for PMSM drives to perform FCS MPCC. Aiming at dc-bus voltage sensor unavailable, a new nonlinear extended state observer(ESO) is developed to estimate dc-bus voltage. In the light of load torque disturbance, a modified isokinetic reaching law is proposed and then outer loop NFISM speed regulator is brought forward to heighten the system robust-ness against load variation and attenuate the chatting level. What’s more, for the sake of decreasing the stator current ripple and improve dynamic response, an inner-loop FCS MPCC scheme is adopted. The proposed NFISM-based FCS MPCC with nonlinear ESO can make PMSM drives have satisfactory speed and torque performance. Compared with PI-based and ISM-based speed reg-ulator, respectively, the proposed NFISM-based one enables FCS MPCC PMSM drive system to have stronger anti-load variation ability and weaker fluctuation. StarSim/Hardware experiments validate the feasibility and effectiveness of the proposed strategy.