The mission sequential logic relations were described by sequential diagram

mission reliability model of each phase and the reliability allocation model were built

and the constraint conditions and the allocation objective were discussed.The adaptive particle swarm optimization (APSO) was designed

which adaptively adjusted the convergence speed by altering the value of weighted coefficient ω during population iterating.With this method

the global results can be searched quickly in the initial stages

and the local results can be obtained effectively in the later stages.By simulation

it shows that the APSO can reach more optimal results and convergence in solving the mission reliability allocation of spaceflight TT&C(tracking telemetry and command) system.