N-type Bi2O2Se has a bright prospect for mid-temperature thermoelectric applications on account of the intrinsically low thermal conductivity. However, the low carrier concentration of Bi2O2Se (similar to 10(15)cm(-3)) severely limits its thermoelectric performance. Herein, the boosting of the carrier concentration to similar to 10(19) cm(-3) can be realized in our La-doped Bi2O2Se ceramic samples, which could be ascribed to the formation of isoelectronic traps and the narrowing of band gap, and contribute to a marked increase in the electrical conductivity (from 0.03S cm(-1) to 182Scm(-1)). Our X-ray absorption near-edge structure spectra results reveal that a local disordering of oxygen atoms could be an important reason for the intrinsically low thermal conductivity of Bi2O2Se, and the point defects can also suppress the lattice thermal conductivity in La-doped Bi2O2Se. The ZT value can be enhanced by a factor of similar to 4.5 to 0.35 at 823K for Bi1.98La0.02O2Se as compared to the pristine Bi2O2Se. The coordinated optimization of electrical and thermal properties demonstrates an effective method for the rational design of high-performance thermoelectric materials.