The TiB2(0001) surfaces are calculated using the first-principles total-energy plane-wave pseudopotentialmethod based on density functional theory. It is found that there are large relaxationswithin the top three layers for both termination surfaces, and the outermost andsecond interlayer relaxations for B-terminated surfaces are much larger than thosefor Ti-terminated surfaces. The charge depletion in the vacuum and the chargeaccumulations in the interlayer region between the first and second layers reinforces theinterlayer Ti–B chemical bonds and reduces the outermost interlayer distance.Simultaneously, the charge accumulation for B-terminated surface is more thanthat for Ti-terminated surface, and the interlayer Ti–B bonds between thesecond and third layers are weakened more for the B-terminated surface. TheTi-terminated surface is thermodynamically more favourable in most of the range ofμBslab.