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To improve thermoelectric properties, we attempt to dope Ti into SiC-based composite by transient plastic phase process (TPPP) method. The final result is composed of the functional phase SiC and the reinforcement phases TiC[sub x] and TiSi[sub 2]. The process of doping is the diffusion of Ti in TiC[sub x] solid-solution into SiC grain at high temperature. When the initial SiC is α-type of 5 µm size, the Seebeck coefficient S is less than 10 µV/K at room temperature. SEM photograph shows the reason being that doping is very weak. We change the initial SiC to the β-type of 90 nm size to aid doping. It is observed that S can be significantly improved to 46.3 µV/K at room temperature. When the temperature rises, the improvement is even greater. Measurements of the lattice parameter of β-SiC show that the parameter parallel to the Si-C layer is almost unchanged and the parameter perpendicular to the Si-C layer increases by about 0.48%, which demonstrated that Ti has been successfully doped into the SiC grain and exists as interstitial impurities. [ABSTRACT FROM AUTHOR]