Influence of Q-switched laser pulse energy (λ = 0.69 μm, t = 15 ns) and the preliminary heating of the substrate upon the extent of the implanted atoms activation (Si ← B+. Si ← P+) as well as the carrier mobility and the electroactive impurity distribution profiles at the laser annealing has been investigated. It has been found out that increase of the heating temperature of a substate from 25°C to 400°C results in essential decrease of the threshold annealing intensity; distribution temperature protiles are used to account for the obtained experimental curves. The influence of phase transitions were taken into account during calculation. The possible mechanisms of the laser annealing of implanted layers are discussed.