To solve problem that cannot be coded, which is inherent in the linear broadcast and linear dispersion, this paper proposes a new type of linear network code—the strict linear dispersion. A construction algorithm is proposed and it proves that the demanded finite field size is not higher than that of linear dispersion. Moreover, some special transition matrices are defined and the transition feasibility from linear dispersion to strict linear dispersion is proved. If combined with a special packetization strategy, the strict linear dispersion can present advantages over linear dispersion when applied in heterogeneous networks. It can also realize multi-rate transmission with a single network code session and provide convenience to the construction of network code on the extended network.