The invention discloses a dynamic allocation realization structure of a satellite-borne treatment resource pool, which comprises a PRACH pilot capture unit, a channel selection unit, a despreading and demodulation resource pool and a time and control unit. The PRACH pilot capture unit extracts user channel signature information contained in input wave beam signals received by a satellite and sends the user channel signature information to the time and control unit. The channel selection unit, according to the selection control instruction of the time and control unit, screens channel signals to be processed from the input wave beam signals received by the satellite and sends the channel signals to the despreading and demodulation resource pool. The despreading and demodulation resource pool receives the screened channel signal to be processed from the channel selection unit and searches for and despreads and demodulates the channel signals to be processed by using parameter information transmitted by the time and control unit. The time and control unit is responsible for the control work of the whole dynamic allocation structure.