We have investigated the joint effect of size- and composition-induced band-gap change of semiconductive nanocompounds from the recently developed bond-order-length-strength (BOLS) correlation mechanism using the approach of local bond average (LBA). An analytical solution has been developed to connect the band-gap energy with the bonding identities of the nanocompounds. Agreement between the model predictions with the available experimental measurements of band-gap change of II-VI semiconductor nanocompounds showed that both the particle size and the composition with alloying effect can be used as factors tuning the band-gap energy, suggesting an effective way to realize the desirable properties of semiconductive nanocompounds. (C) 2008 Elsevier B.V. All rights reserved.